diff --git a/interweb-core/src/main/java/de/l3s/interweb/core/util/DateUtils.java b/interweb-core/src/main/java/de/l3s/interweb/core/util/DateUtils.java
index a15a9a74..6d0474ec 100644
--- a/interweb-core/src/main/java/de/l3s/interweb/core/util/DateUtils.java
+++ b/interweb-core/src/main/java/de/l3s/interweb/core/util/DateUtils.java
@@ -21,7 +21,7 @@ public static Instant parse(String str) {
         try {
             return Instant.from(PARSE_FORMAT.parse(str));
         } catch (DateTimeParseException e) {
-            throw new ConnectorException("Unable to parse date: " + str, e);
+            throw new ConnectorException("Unable to parse date in a string `" + str + "`", e);
         }
     }
 
diff --git a/interweb-server/src/main/java/de/l3s/interweb/server/config/ExceptionMappers.java b/interweb-server/src/main/java/de/l3s/interweb/server/config/ExceptionMappers.java
index 9ffcc5ff..ea24a7b1 100644
--- a/interweb-server/src/main/java/de/l3s/interweb/server/config/ExceptionMappers.java
+++ b/interweb-server/src/main/java/de/l3s/interweb/server/config/ExceptionMappers.java
@@ -1,12 +1,23 @@
 package de.l3s.interweb.server.config;
 
 import jakarta.ws.rs.BadRequestException;
+import jakarta.ws.rs.NotFoundException;
 import jakarta.ws.rs.core.Response;
 
 import org.jboss.resteasy.reactive.RestResponse;
 import org.jboss.resteasy.reactive.server.ServerExceptionMapper;
 
 public class ExceptionMappers {
+    @ServerExceptionMapper
+    public RestResponse<HttpError> mapException(Exception x) {
+        return RestResponse.status(Response.Status.INTERNAL_SERVER_ERROR, HttpError.of(x));
+    }
+
+    @ServerExceptionMapper
+    public RestResponse<HttpError> mapException(NotFoundException x) {
+        return RestResponse.status(Response.Status.NOT_FOUND, HttpError.of(x));
+    }
+
     @ServerExceptionMapper
     public RestResponse<HttpError> mapException(BadRequestException x) {
         return RestResponse.status(Response.Status.BAD_REQUEST, HttpError.of(x));
diff --git a/interweb-server/src/main/java/de/l3s/interweb/server/features/chat/ChatService.java b/interweb-server/src/main/java/de/l3s/interweb/server/features/chat/ChatService.java
index fde771f3..d2b1e486 100644
--- a/interweb-server/src/main/java/de/l3s/interweb/server/features/chat/ChatService.java
+++ b/interweb-server/src/main/java/de/l3s/interweb/server/features/chat/ChatService.java
@@ -24,7 +24,7 @@ public Uni<CompletionsResults> completions(CompletionsQuery query) {
                 return completions(query, model, chatConnector);
             }
 
-            return Uni.createFrom().failure(new ConnectorException("Model doesn't support chat: " + query.getModel()));
+            return Uni.createFrom().failure(new ConnectorException("Model `" + query.getModel() + "` is not a chat model"));
         });
     }
 
diff --git a/interweb-server/src/main/java/de/l3s/interweb/server/features/describe/DescribeService.java b/interweb-server/src/main/java/de/l3s/interweb/server/features/describe/DescribeService.java
index 20a89fb3..add82d55 100644
--- a/interweb-server/src/main/java/de/l3s/interweb/server/features/describe/DescribeService.java
+++ b/interweb-server/src/main/java/de/l3s/interweb/server/features/describe/DescribeService.java
@@ -36,7 +36,7 @@ private DescribeConnector getConnector(Set<String> services) {
         String val = services.iterator().next();
         DescribeConnector connector = this.services.get(val.toLowerCase(Locale.ROOT));
         if (connector == null) {
-            throw new ConnectorException("Unknown service: " + val);
+            throw new ConnectorException("Service `" + val + "` is unknown");
         }
         return connector;
     }
diff --git a/interweb-server/src/main/java/de/l3s/interweb/server/features/models/ModelsService.java b/interweb-server/src/main/java/de/l3s/interweb/server/features/models/ModelsService.java
index 4c199262..8c6ca422 100644
--- a/interweb-server/src/main/java/de/l3s/interweb/server/features/models/ModelsService.java
+++ b/interweb-server/src/main/java/de/l3s/interweb/server/features/models/ModelsService.java
@@ -66,6 +66,6 @@ public Uni<List<Model>> getModels() {
     public Uni<Model> getModel(String modelId) {
         return getModels().map(models -> models.stream()
                 .filter(model -> model.getId().equalsIgnoreCase(modelId.toLowerCase(Locale.ROOT)))
-                .findFirst().orElseThrow(() -> new NotFoundException("Model not found: " + modelId)));
+                .findFirst().orElseThrow(() -> new NotFoundException("Model `" + modelId + "` not found")));
     }
 }
diff --git a/interweb-server/src/main/java/de/l3s/interweb/server/features/search/SearchService.java b/interweb-server/src/main/java/de/l3s/interweb/server/features/search/SearchService.java
index 7aab0d88..dff18a30 100644
--- a/interweb-server/src/main/java/de/l3s/interweb/server/features/search/SearchService.java
+++ b/interweb-server/src/main/java/de/l3s/interweb/server/features/search/SearchService.java
@@ -49,7 +49,7 @@ private Collection<SearchConnector> getConnectors(Set<String> services) {
             return services.stream().map(val -> {
                 SearchConnector connector = this.providers.get(val.toLowerCase(Locale.ROOT));
                 if (connector == null) {
-                    throw new ConnectorException("Unknown service: " + val);
+                    throw new ConnectorException("Service `" + val + "` is unknown");
                 }
                 return connector;
             }).toList();
diff --git a/interweb-server/src/main/java/de/l3s/interweb/server/features/suggest/SuggestService.java b/interweb-server/src/main/java/de/l3s/interweb/server/features/suggest/SuggestService.java
index c4da0aee..f670e70a 100644
--- a/interweb-server/src/main/java/de/l3s/interweb/server/features/suggest/SuggestService.java
+++ b/interweb-server/src/main/java/de/l3s/interweb/server/features/suggest/SuggestService.java
@@ -39,7 +39,7 @@ private Collection<SuggestConnector> getConnectors(Set<String> services) {
             return services.stream().map(val -> {
                 SuggestConnector connector = this.services.get(val.toLowerCase(Locale.ROOT));
                 if (connector == null) {
-                    throw new ConnectorException("Unknown service: " + val);
+                    throw new ConnectorException("Service `" + val + "` is unknown");
                 }
                 return connector;
             }).toList();
@@ -52,7 +52,7 @@ public void validateServices(Set<String> services) {
         if (services != null && !services.isEmpty()) {
             for (String service : services) {
                 if (!this.services.containsKey(service)) {
-                    throw new ValidationException("Service unknown.");
+                    throw new ValidationException("Service unknown");
                 }
             }
         }