diff --git a/docs/model_access_control.md b/docs/model_access_control.md
index fb80b49e96..2fac5bca73 100644
--- a/docs/model_access_control.md
+++ b/docs/model_access_control.md
@@ -178,7 +178,7 @@ Updating a model group request is very similar to register model group request.
 ### Path and HTTP method
 
 ```
-PUT /_plugins/_ml/model_groups/<model_group_id>/_update
+PUT /_plugins/_ml/model_groups/<model_group_id>
 ```
 
 A user can make updates to a model group to which he/she has access which is determined by the access mode of the model group.
@@ -196,7 +196,7 @@ For example,
 Sample request allowed by admin/owner
 
 ```
-PUT /_plugins/_ml/model_groups/<model_group_id>/_update
+PUT /_plugins/_ml/model_groups/<model_group_id>
 {
   "name": "model_group_test",
   "description": "This is an example description",
@@ -215,7 +215,7 @@ PUT /_plugins/_ml/model_groups/<model_group_id>/_update
 Sample update request allowed by any other user with access to model group.
 
 ```
-PUT /_plugins/_ml/model_groups/<model_group_id>/_update
+PUT /_plugins/_ml/model_groups/<model_group_id>
 {
     "name": "model_group_test",
     "description": "This is an example description"
diff --git a/plugin/src/main/java/org/opensearch/ml/action/model_group/TransportUpdateModelGroupAction.java b/plugin/src/main/java/org/opensearch/ml/action/model_group/TransportUpdateModelGroupAction.java
index 49efb64b65..039d9cb4f8 100644
--- a/plugin/src/main/java/org/opensearch/ml/action/model_group/TransportUpdateModelGroupAction.java
+++ b/plugin/src/main/java/org/opensearch/ml/action/model_group/TransportUpdateModelGroupAction.java
@@ -14,6 +14,7 @@
 import java.util.Map;
 
 import org.apache.commons.lang3.StringUtils;
+import org.opensearch.OpenSearchStatusException;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.get.GetRequest;
@@ -41,6 +42,7 @@
 import org.opensearch.ml.model.MLModelGroupManager;
 import org.opensearch.ml.utils.MLNodeUtils;
 import org.opensearch.ml.utils.RestActionUtils;
+import org.opensearch.rest.RestStatus;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
@@ -101,7 +103,7 @@ protected void doExecute(Task task, ActionRequest request, ActionListener<MLUpda
                             updateModelGroup(modelGroupId, modelGroup.getSource(), updateModelGroupInput, listener, user);
                         }
                     } else {
-                        listener.onFailure(new MLResourceNotFoundException("Failed to find model group"));
+                        listener.onFailure(new OpenSearchStatusException("Failed to find model group", RestStatus.NOT_FOUND));
                     }
                 }, e -> {
                     if (e instanceof IndexNotFoundException) {
@@ -197,18 +199,18 @@ private void validateRequestForAccessControl(MLUpdateModelGroupInput input, User
         if (hasAccessControlChange(input)) {
             if (!modelAccessControlHelper.isOwner(mlModelGroup.getOwner(), user) && !modelAccessControlHelper.isAdmin(user)) {
                 throw new IllegalArgumentException("Only owner or admin can update access control data.");
-            } else if (modelAccessControlHelper.isOwner(mlModelGroup.getOwner(), user)
-                && !modelAccessControlHelper.isAdmin(user)
-                && !modelAccessControlHelper.isOwnerStillHasPermission(user, mlModelGroup)) {
-                throw new IllegalArgumentException(
-                    "You don’t have the specified backend role to update access control data. For more information, contact your administrator."
-                );
             }
         }
         if (!modelAccessControlHelper.isAdmin(user)
             && !modelAccessControlHelper.isOwner(mlModelGroup.getOwner(), user)
             && !modelAccessControlHelper.isUserHasBackendRole(user, mlModelGroup)) {
             throw new IllegalArgumentException("You don't have permission to update this model group.");
+        } else if (modelAccessControlHelper.isOwner(mlModelGroup.getOwner(), user)
+            && !modelAccessControlHelper.isAdmin(user)
+            && !modelAccessControlHelper.isOwnerStillHasPermission(user, mlModelGroup)) {
+            throw new IllegalArgumentException(
+                "You don’t have the specified backend role to update access control data. For more information, contact your administrator."
+            );
         }
         AccessMode accessMode = input.getModelAccessMode();
         if ((AccessMode.PUBLIC == accessMode || AccessMode.PRIVATE == accessMode)
diff --git a/plugin/src/main/java/org/opensearch/ml/action/models/GetModelTransportAction.java b/plugin/src/main/java/org/opensearch/ml/action/models/GetModelTransportAction.java
index d73c1c7bbf..05c4deaa86 100644
--- a/plugin/src/main/java/org/opensearch/ml/action/models/GetModelTransportAction.java
+++ b/plugin/src/main/java/org/opensearch/ml/action/models/GetModelTransportAction.java
@@ -11,6 +11,7 @@
 import static org.opensearch.ml.utils.MLNodeUtils.createXContentParserFromRegistry;
 import static org.opensearch.ml.utils.RestActionUtils.getFetchSourceContext;
 
+import org.opensearch.OpenSearchStatusException;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.get.GetRequest;
@@ -34,6 +35,7 @@
 import org.opensearch.ml.common.transport.model.MLModelGetResponse;
 import org.opensearch.ml.helper.ModelAccessControlHelper;
 import org.opensearch.ml.utils.RestActionUtils;
+import org.opensearch.rest.RestStatus;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
@@ -110,7 +112,13 @@ protected void doExecute(Task task, ActionRequest request, ActionListener<MLMode
                         actionListener.onFailure(e);
                     }
                 } else {
-                    actionListener.onFailure(new IllegalArgumentException("Failed to find model with the provided model id: " + modelId));
+                    actionListener
+                        .onFailure(
+                            new OpenSearchStatusException(
+                                "Failed to find model with the provided model id: " + modelId,
+                                RestStatus.NOT_FOUND
+                            )
+                        );
                 }
             }, e -> {
                 if (e instanceof IndexNotFoundException) {
diff --git a/plugin/src/main/java/org/opensearch/ml/action/tasks/GetTaskTransportAction.java b/plugin/src/main/java/org/opensearch/ml/action/tasks/GetTaskTransportAction.java
index 6fd84e372f..11e9c67d2c 100644
--- a/plugin/src/main/java/org/opensearch/ml/action/tasks/GetTaskTransportAction.java
+++ b/plugin/src/main/java/org/opensearch/ml/action/tasks/GetTaskTransportAction.java
@@ -9,6 +9,7 @@
 import static org.opensearch.ml.common.CommonValue.ML_TASK_INDEX;
 import static org.opensearch.ml.utils.MLNodeUtils.createXContentParserFromRegistry;
 
+import org.opensearch.OpenSearchStatusException;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.get.GetRequest;
@@ -25,6 +26,7 @@
 import org.opensearch.ml.common.transport.task.MLTaskGetAction;
 import org.opensearch.ml.common.transport.task.MLTaskGetRequest;
 import org.opensearch.ml.common.transport.task.MLTaskGetResponse;
+import org.opensearch.rest.RestStatus;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
@@ -68,7 +70,7 @@ protected void doExecute(Task task, ActionRequest request, ActionListener<MLTask
                         actionListener.onFailure(e);
                     }
                 } else {
-                    actionListener.onFailure(new MLResourceNotFoundException("Fail to find task"));
+                    actionListener.onFailure(new OpenSearchStatusException("Fail to find task", RestStatus.NOT_FOUND));
                 }
             }, e -> {
                 if (e instanceof IndexNotFoundException) {
diff --git a/plugin/src/main/java/org/opensearch/ml/model/MLModelManager.java b/plugin/src/main/java/org/opensearch/ml/model/MLModelManager.java
index b9208187fc..02d3889464 100644
--- a/plugin/src/main/java/org/opensearch/ml/model/MLModelManager.java
+++ b/plugin/src/main/java/org/opensearch/ml/model/MLModelManager.java
@@ -63,6 +63,7 @@
 import java.util.function.Supplier;
 
 import org.apache.logging.log4j.util.Strings;
+import org.opensearch.OpenSearchStatusException;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.delete.DeleteRequest;
 import org.opensearch.action.get.GetRequest;
@@ -891,7 +892,7 @@ public void getModel(String modelId, String[] includes, String[] excludes, Actio
                     listener.onFailure(e);
                 }
             } else {
-                listener.onFailure(new MLResourceNotFoundException("Fail to find model"));
+                listener.onFailure(new OpenSearchStatusException("Failed to find model", RestStatus.NOT_FOUND));
             }
         }, e -> { listener.onFailure(e); }));
     }
diff --git a/plugin/src/main/java/org/opensearch/ml/rest/RestMLPredictionAction.java b/plugin/src/main/java/org/opensearch/ml/rest/RestMLPredictionAction.java
index df5b098576..14f4d882d3 100644
--- a/plugin/src/main/java/org/opensearch/ml/rest/RestMLPredictionAction.java
+++ b/plugin/src/main/java/org/opensearch/ml/rest/RestMLPredictionAction.java
@@ -99,7 +99,7 @@ public RestChannelConsumer prepareRequest(RestRequest request, NodeClient client
             }, e -> {
                 log.error("Failed to get ML model", e);
                 try {
-                    channel.sendResponse(new BytesRestResponse(channel, RestStatus.BAD_REQUEST, e));
+                    channel.sendResponse(new BytesRestResponse(channel, RestStatus.NOT_FOUND, e));
                 } catch (IOException ex) {
                     log.error("Failed to send error response", ex);
                 }
diff --git a/plugin/src/main/java/org/opensearch/ml/rest/RestMLUpdateModelGroupAction.java b/plugin/src/main/java/org/opensearch/ml/rest/RestMLUpdateModelGroupAction.java
index 34ccca9c15..87f64e0c5b 100644
--- a/plugin/src/main/java/org/opensearch/ml/rest/RestMLUpdateModelGroupAction.java
+++ b/plugin/src/main/java/org/opensearch/ml/rest/RestMLUpdateModelGroupAction.java
@@ -38,10 +38,7 @@ public String getName() {
     public List<Route> routes() {
         return ImmutableList
             .of(
-                new Route(
-                    RestRequest.Method.PUT,
-                    String.format(Locale.ROOT, "%s/model_groups/{%s}/_update", ML_BASE_URI, PARAMETER_MODEL_GROUP_ID)
-                )
+                new Route(RestRequest.Method.PUT, String.format(Locale.ROOT, "%s/model_groups/{%s}", ML_BASE_URI, PARAMETER_MODEL_GROUP_ID))
             );
     }
 
diff --git a/plugin/src/test/java/org/opensearch/ml/action/models/DeleteModelTransportActionTests.java b/plugin/src/test/java/org/opensearch/ml/action/models/DeleteModelTransportActionTests.java
index 73bd333985..245c7a86e2 100644
--- a/plugin/src/test/java/org/opensearch/ml/action/models/DeleteModelTransportActionTests.java
+++ b/plugin/src/test/java/org/opensearch/ml/action/models/DeleteModelTransportActionTests.java
@@ -147,7 +147,7 @@ public void testDeleteModel_Success() throws IOException {
             return null;
         }).when(client).execute(any(), any(), any());
 
-        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED);
+        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED, null);
         doAnswer(invocation -> {
             ActionListener<GetResponse> actionListener = invocation.getArgument(1);
             actionListener.onResponse(getResponse);
@@ -172,16 +172,7 @@ public void testDeleteModel_Success_AlgorithmNotNull() throws IOException {
             return null;
         }).when(client).execute(any(), any(), any());
 
-        MLModel mlModel = MLModel
-            .builder()
-            .modelId("test_id")
-            .modelState(MLModelState.REGISTERED)
-            .algorithm(FunctionName.TEXT_EMBEDDING)
-            .build();
-        XContentBuilder content = mlModel.toXContent(XContentFactory.jsonBuilder(), ToXContent.EMPTY_PARAMS);
-        BytesReference bytesReference = BytesReference.bytes(content);
-        GetResult getResult = new GetResult("indexName", "111", 111l, 111l, 111l, true, bytesReference, null, null);
-        GetResponse getResponse = new GetResponse(getResult);
+        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED, null);
         doAnswer(invocation -> {
             ActionListener<GetResponse> actionListener = invocation.getArgument(1);
             actionListener.onResponse(getResponse);
@@ -213,17 +204,8 @@ public void test_Success_ModelGroupIDNotNull_LastModelOfGroup() throws IOExcepti
             return null;
         }).when(client).search(any(), isA(ActionListener.class));
 
-        MLModel mlModel = MLModel
-            .builder()
-            .modelId("test_id")
-            .modelGroupId("modelGroupID")
-            .modelState(MLModelState.REGISTERED)
-            .algorithm(FunctionName.TEXT_EMBEDDING)
-            .build();
-        XContentBuilder content = mlModel.toXContent(XContentFactory.jsonBuilder(), ToXContent.EMPTY_PARAMS);
-        BytesReference bytesReference = BytesReference.bytes(content);
-        GetResult getResult = new GetResult("indexName", "111", 111l, 111l, 111l, true, bytesReference, null, null);
-        GetResponse getResponse = new GetResponse(getResult);
+        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED, "modelGroupID");
+
         doAnswer(invocation -> {
             ActionListener<GetResponse> actionListener = invocation.getArgument(1);
             actionListener.onResponse(getResponse);
@@ -296,17 +278,8 @@ public void test_Failure_FailedToSearchLastModel() throws IOException {
             return null;
         }).when(client).search(any(), isA(ActionListener.class));
 
-        MLModel mlModel = MLModel
-            .builder()
-            .modelId("test_id")
-            .modelGroupId("modelGroupID")
-            .modelState(MLModelState.REGISTERED)
-            .algorithm(FunctionName.TEXT_EMBEDDING)
-            .build();
-        XContentBuilder content = mlModel.toXContent(XContentFactory.jsonBuilder(), ToXContent.EMPTY_PARAMS);
-        BytesReference bytesReference = BytesReference.bytes(content);
-        GetResult getResult = new GetResult("indexName", "111", 111l, 111l, 111l, true, bytesReference, null, null);
-        GetResponse getResponse = new GetResponse(getResult);
+        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED, "modelGroupID");
+
         doAnswer(invocation -> {
             ActionListener<GetResponse> actionListener = invocation.getArgument(1);
             actionListener.onResponse(getResponse);
@@ -320,7 +293,7 @@ public void test_Failure_FailedToSearchLastModel() throws IOException {
     }
 
     public void test_UserHasNoAccessException() throws IOException {
-        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED);
+        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED, "modelGroupID");
         doAnswer(invocation -> {
             ActionListener<GetResponse> actionListener = invocation.getArgument(1);
             actionListener.onResponse(getResponse);
@@ -340,7 +313,7 @@ public void test_UserHasNoAccessException() throws IOException {
     }
 
     public void testDeleteModel_CheckModelState() throws IOException {
-        GetResponse getResponse = prepareMLModel(MLModelState.DEPLOYING);
+        GetResponse getResponse = prepareMLModel(MLModelState.DEPLOYING, null);
         doAnswer(invocation -> {
             ActionListener<GetResponse> actionListener = invocation.getArgument(1);
             actionListener.onResponse(getResponse);
@@ -383,7 +356,7 @@ public void testDeleteModel_ResourceNotFoundException() throws IOException {
             return null;
         }).when(client).execute(any(), any(), any());
 
-        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED);
+        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED, null);
         doAnswer(invocation -> {
             ActionListener<GetResponse> actionListener = invocation.getArgument(1);
             actionListener.onResponse(getResponse);
@@ -397,7 +370,7 @@ public void testDeleteModel_ResourceNotFoundException() throws IOException {
     }
 
     public void test_ValidationFailedException() throws IOException {
-        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED);
+        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED, null);
         doAnswer(invocation -> {
             ActionListener<GetResponse> actionListener = invocation.getArgument(1);
             actionListener.onResponse(getResponse);
@@ -441,7 +414,7 @@ public void testDeleteModelChunks_Success() {
     }
 
     public void testDeleteModel_RuntimeException() throws IOException {
-        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED);
+        GetResponse getResponse = prepareMLModel(MLModelState.REGISTERED, null);
         doAnswer(invocation -> {
             ActionListener<GetResponse> actionListener = invocation.getArgument(1);
             actionListener.onResponse(getResponse);
@@ -535,8 +508,8 @@ public void test_FailToDeleteAllModelChunks_SearchFailure() {
         assertEquals(OS_STATUS_EXCEPTION_MESSAGE + ", " + SEARCH_FAILURE_MSG + "test_id", argumentCaptor.getValue().getMessage());
     }
 
-    public GetResponse prepareMLModel(MLModelState mlModelState) throws IOException {
-        MLModel mlModel = MLModel.builder().modelId("test_id").modelState(mlModelState).build();
+    public GetResponse prepareMLModel(MLModelState mlModelState, String modelGroupID) throws IOException {
+        MLModel mlModel = MLModel.builder().modelId("test_id").modelState(mlModelState).modelGroupId(modelGroupID).build();
         XContentBuilder content = mlModel.toXContent(XContentFactory.jsonBuilder(), ToXContent.EMPTY_PARAMS);
         BytesReference bytesReference = BytesReference.bytes(content);
         GetResult getResult = new GetResult("indexName", "111", 111l, 111l, 111l, true, bytesReference, null, null);
diff --git a/plugin/src/test/java/org/opensearch/ml/model/MLModelGroupManagerTests.java b/plugin/src/test/java/org/opensearch/ml/model/MLModelGroupManagerTests.java
index 0bb2c10632..54a78fc921 100644
--- a/plugin/src/test/java/org/opensearch/ml/model/MLModelGroupManagerTests.java
+++ b/plugin/src/test/java/org/opensearch/ml/model/MLModelGroupManagerTests.java
@@ -38,6 +38,7 @@
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
+@Ignore
 public class MLModelGroupManagerTests extends OpenSearchTestCase {
     @Rule
     public ExpectedException exceptionRule = ExpectedException.none();
@@ -105,7 +106,6 @@ public void setup() {
         when(threadPool.getThreadContext()).thenReturn(threadContext);
     }
 
-    @Ignore
     public void test_SuccessAddAllBackendRolesTrue() {
         threadContext.putTransient(ConfigConstants.OPENSEARCH_SECURITY_USER_INFO_THREAD_CONTEXT, "alex|IT,HR|engineering,operations");
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(true);
@@ -116,7 +116,6 @@ public void test_SuccessAddAllBackendRolesTrue() {
         verify(actionListener).onResponse(argumentCaptor.capture());
     }
 
-    @Ignore
     public void test_SuccessPublic() {
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(true);
 
@@ -126,7 +125,6 @@ public void test_SuccessPublic() {
         verify(actionListener).onResponse(argumentCaptor.capture());
     }
 
-    @Ignore
     public void test_ExceptionAllAccessFieldsNull() {
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(true);
 
@@ -140,7 +138,6 @@ public void test_ExceptionAllAccessFieldsNull() {
         );
     }
 
-    @Ignore
     public void test_ModelAccessModeNullAddAllBackendRolesTrue() {
         threadContext.putTransient(ConfigConstants.OPENSEARCH_SECURITY_USER_INFO_THREAD_CONTEXT, "alex|IT,HR|engineering,operations");
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(true);
@@ -151,7 +148,6 @@ public void test_ModelAccessModeNullAddAllBackendRolesTrue() {
         verify(actionListener).onResponse(argumentCaptor.capture());
     }
 
-    @Ignore
     public void test_BackendRolesProvidedWithPublic() {
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(true);
 
@@ -162,7 +158,6 @@ public void test_BackendRolesProvidedWithPublic() {
         assertEquals("You can specify backend roles only for a model group with the restricted access mode.", argumentCaptor.getValue().getMessage());
     }
 
-    @Ignore
     public void test_BackendRolesProvidedWithPrivate() {
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(true);
 
@@ -173,7 +168,6 @@ public void test_BackendRolesProvidedWithPrivate() {
         assertEquals("You can specify backend roles only for a model group with the restricted access mode.", argumentCaptor.getValue().getMessage());
     }
 
-    @Ignore
     public void test_AdminSpecifiedAddAllBackendRolesForRestricted() {
         threadContext.putTransient(ConfigConstants.OPENSEARCH_SECURITY_USER_INFO_THREAD_CONTEXT, "admin|admin|all_access");
         when(modelAccessControlHelper.isAdmin(any())).thenReturn(true);
@@ -186,7 +180,6 @@ public void test_AdminSpecifiedAddAllBackendRolesForRestricted() {
         assertEquals("Admin users cannot add all backend roles to a model group.", argumentCaptor.getValue().getMessage());
     }
 
-    @Ignore
     public void test_UserWithNoBackendRolesSpecifiedRestricted() {
         threadContext.putTransient(ConfigConstants.OPENSEARCH_SECURITY_USER_INFO_THREAD_CONTEXT, "alex||engineering,operations");
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(true);
@@ -201,7 +194,6 @@ public void test_UserWithNoBackendRolesSpecifiedRestricted() {
         );
     }
 
-    @Ignore
     public void test_UserSpecifiedRestrictedButNoBackendRolesFieldF() {
         threadContext.putTransient(ConfigConstants.OPENSEARCH_SECURITY_USER_INFO_THREAD_CONTEXT, "alex|IT,HR|engineering,operations");
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(true);
@@ -216,7 +208,6 @@ public void test_UserSpecifiedRestrictedButNoBackendRolesFieldF() {
         );
     }
 
-    @Ignore
     public void test_RestrictedAndUserSpecifiedBothBackendRolesField() {
         threadContext.putTransient(ConfigConstants.OPENSEARCH_SECURITY_USER_INFO_THREAD_CONTEXT, "alex|IT,HR|engineering,operations");
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(true);
@@ -231,7 +222,6 @@ public void test_RestrictedAndUserSpecifiedBothBackendRolesField() {
         );
     }
 
-    @Ignore
     public void test_RestrictedAndUserSpecifiedIncorrectBackendRoles() {
         threadContext.putTransient(ConfigConstants.OPENSEARCH_SECURITY_USER_INFO_THREAD_CONTEXT, "alex|IT,HR|engineering,operations");
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(true);
@@ -245,7 +235,6 @@ public void test_RestrictedAndUserSpecifiedIncorrectBackendRoles() {
         assertEquals("You don't have the backend roles specified.", argumentCaptor.getValue().getMessage());
     }
 
-    @Ignore
     public void test_SuccessSecurityDisabledCluster() {
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(false);
 
@@ -255,7 +244,6 @@ public void test_SuccessSecurityDisabledCluster() {
         verify(actionListener).onResponse(argumentCaptor.capture());
     }
 
-    @Ignore
     public void test_ExceptionSecurityDisabledCluster() {
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(false);
 
@@ -269,7 +257,6 @@ public void test_ExceptionSecurityDisabledCluster() {
         );
     }
 
-    @Ignore
     public void test_ExceptionFailedToInitModelGroupIndex() {
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(true);
 
@@ -279,7 +266,6 @@ public void test_ExceptionFailedToInitModelGroupIndex() {
         verify(actionListener).onFailure(argumentCaptor.capture());
     }
 
-    @Ignore
     public void test_ExceptionFailedToIndexModelGroup() {
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(false);
         doAnswer(invocation -> {
@@ -295,7 +281,6 @@ public void test_ExceptionFailedToIndexModelGroup() {
         assertEquals("Index Not Found", argumentCaptor.getValue().getMessage());
     }
 
-    @Ignore
     public void test_ExceptionInitModelGroupIndexIfAbsent() {
         when(modelAccessControlHelper.isSecurityEnabledAndModelAccessControlEnabled(any())).thenReturn(false);
         doAnswer(invocation -> {
diff --git a/plugin/src/test/java/org/opensearch/ml/model/MLModelManagerTests.java b/plugin/src/test/java/org/opensearch/ml/model/MLModelManagerTests.java
index 1e2ebefea3..07c87c65fd 100644
--- a/plugin/src/test/java/org/opensearch/ml/model/MLModelManagerTests.java
+++ b/plugin/src/test/java/org/opensearch/ml/model/MLModelManagerTests.java
@@ -483,7 +483,7 @@ public void testDeployModel_NullGetModelResponse() {
         assertFalse(modelManager.isModelRunningOnNode(modelId));
         ArgumentCaptor<Exception> exception = ArgumentCaptor.forClass(Exception.class);
         verify(listener).onFailure(exception.capture());
-        assertEquals("Fail to find model", exception.getValue().getMessage());
+        assertEquals("Failed to find model", exception.getValue().getMessage());
         verify(mlStats)
             .createCounterStatIfAbsent(
                 eq(FunctionName.TEXT_EMBEDDING),
@@ -503,7 +503,7 @@ public void testDeployModel_GetModelResponse_NotExist() {
         assertFalse(modelManager.isModelRunningOnNode(modelId));
         ArgumentCaptor<Exception> exception = ArgumentCaptor.forClass(Exception.class);
         verify(listener).onFailure(exception.capture());
-        assertEquals("Fail to find model", exception.getValue().getMessage());
+        assertEquals("Failed to find model", exception.getValue().getMessage());
         verify(mlStats)
             .createCounterStatIfAbsent(
                 eq(FunctionName.TEXT_EMBEDDING),
diff --git a/plugin/src/test/java/org/opensearch/ml/rest/MLCommonsRestTestCase.java b/plugin/src/test/java/org/opensearch/ml/rest/MLCommonsRestTestCase.java
index e2cbf33f15..13e40ed292 100644
--- a/plugin/src/test/java/org/opensearch/ml/rest/MLCommonsRestTestCase.java
+++ b/plugin/src/test/java/org/opensearch/ml/rest/MLCommonsRestTestCase.java
@@ -697,8 +697,7 @@ public void registerModelGroup(RestClient client, String input, Consumer<Map<Str
 
     public void updateModelGroup(RestClient client, String modelGroupId, String input, Consumer<Map<String, Object>> function)
         throws IOException {
-        Response response = TestHelper
-            .makeRequest(client, "PUT", "/_plugins/_ml/model_groups/" + modelGroupId + "/_update", null, input, null);
+        Response response = TestHelper.makeRequest(client, "PUT", "/_plugins/_ml/model_groups/" + modelGroupId, null, input, null);
         verifyResponse(function, response);
     }
 
diff --git a/plugin/src/test/java/org/opensearch/ml/rest/RestMLUpdateModelGroupActionTests.java b/plugin/src/test/java/org/opensearch/ml/rest/RestMLUpdateModelGroupActionTests.java
index b51a1d279e..4be74e6370 100644
--- a/plugin/src/test/java/org/opensearch/ml/rest/RestMLUpdateModelGroupActionTests.java
+++ b/plugin/src/test/java/org/opensearch/ml/rest/RestMLUpdateModelGroupActionTests.java
@@ -91,7 +91,7 @@ public void testRoutes() {
         assertFalse(routes.isEmpty());
         RestHandler.Route route = routes.get(0);
         assertEquals(RestRequest.Method.PUT, route.getMethod());
-        assertEquals("/_plugins/_ml/model_groups/{model_group_id}/_update", route.getPath());
+        assertEquals("/_plugins/_ml/model_groups/{model_group_id}", route.getPath());
     }
 
     public void testUpdateModelGroupRequest() throws Exception {
@@ -119,7 +119,7 @@ private RestRequest getRestRequest() {
         params.put("model_group_id", "test_modelGroupId");
         RestRequest request = new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY)
             .withMethod(method)
-            .withPath("/_plugins/_ml/model_groups/{model_group_id}/_update")
+            .withPath("/_plugins/_ml/model_groups/{model_group_id}")
             .withParams(params)
             .withContent(new BytesArray(requestContent), XContentType.JSON)
             .build();
@@ -132,7 +132,7 @@ private RestRequest getRestRequestWithEmptyContent() {
         params.put("model_group_id", "test_modelGroupId");
         RestRequest request = new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY)
             .withMethod(method)
-            .withPath("/_plugins/_ml/model_groups/{model_group_id}/_update")
+            .withPath("/_plugins/_ml/model_groups/{model_group_id}")
             .withParams(params)
             .withContent(new BytesArray(""), XContentType.JSON)
             .build();