diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index dd7699b..757942a 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -5,7 +5,6 @@
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
     <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
-    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />
@@ -18,6 +17,7 @@
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
+        android:networkSecurityConfig="@xml/network_security_config"
         android:theme="@style/AppTheme">
         <provider
             android:name="androidx.core.content.FileProvider"
diff --git a/app/src/main/java/me/gensh/service/CampusNetworkTest.java b/app/src/main/java/me/gensh/service/CampusNetworkTest.java
index a3d9bb0..7a74ad1 100644
--- a/app/src/main/java/me/gensh/service/CampusNetworkTest.java
+++ b/app/src/main/java/me/gensh/service/CampusNetworkTest.java
@@ -39,8 +39,6 @@
  */
 
 public class CampusNetworkTest extends IntentService implements HttpRequestTask.OnTaskFinished {
-    final String TEST_URL = "http://www.sohu.com";
-    final String TEST_TAG = "test connection";
     final static String INTENT_EXTRA_SSID = "ssid";
     final int NETWORK_SING_IN_NOTIFY_ID = 10;
     final int AUTO_SIGN_IN_ERROR_NOTIFY_ID = 12;
diff --git a/app/src/main/res/xml/network_security_config.xml b/app/src/main/res/xml/network_security_config.xml
new file mode 100644
index 0000000..7d3a8fd
--- /dev/null
+++ b/app/src/main/res/xml/network_security_config.xml
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<network-security-config xmlns:android="http://schemas.android.com/apk/res/android">
+    <domain-config cleartextTrafficPermitted="true">
+        <domain includeSubdomains="false">teach.ustb.edu.cn</domain>
+        <domain includeSubdomains="false">elearning.ustb.edu.cn</domain>
+        <domain includeSubdomains="false">e.ustb.edu.cn</domain>
+        <domain includeSubdomains="false">h.ustb.edu.cn</domain>
+        <domain includeSubdomains="false">202.204.48.82</domain>
+        <domain includeSubdomains="false">202.204.48.66</domain>
+        <domain includeSubdomains="false">zhiyuan.ustb.edu.cn</domain>
+        <domain includeSubdomains="false">lib.ustb.edu.cn</domain>
+        <domain includeSubdomains="false">lib1.ustb.edu.cn</domain>
+        <domain includeSubdomains="false">connect.rom.miui.com</domain>
+    </domain-config>
+</network-security-config>
diff --git a/http-ustb/build.gradle b/http-ustb/build.gradle
index df36e76..93f5069 100644
--- a/http-ustb/build.gradle
+++ b/http-ustb/build.gradle
@@ -7,7 +7,7 @@ tasks.withType(JavaCompile) {
 
 dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
-    compile 'com.squareup.okhttp3:okhttp:3.10.0'
+    compile 'com.squareup.okhttp3:okhttp:4.0.0'
     compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
 }
 sourceCompatibility = "1.7"
diff --git a/http-ustb/src/main/java/me/gensh/helloustb/http/portal/WifiPortal.kt b/http-ustb/src/main/java/me/gensh/helloustb/http/portal/WifiPortal.kt
index 180ef16..cb82eef 100644
--- a/http-ustb/src/main/java/me/gensh/helloustb/http/portal/WifiPortal.kt
+++ b/http-ustb/src/main/java/me/gensh/helloustb/http/portal/WifiPortal.kt
@@ -28,12 +28,12 @@ class WifiPortal {
             try {
                 val response: Response = client.newCall(request).execute()
                 val status = Status()
-                if (response.code() == 200) { //not 204.
+                if (response.code == 200) { //not 204.
                     status.needAuth = true
                     // try to resolve html content.
                     // <html><head><script type="text/javascript">location.href="http://202.204.48.66"</script></head><body><a href="http://202.204.48.66"></a></body></html>
-                    if (response.body() != null) {
-                        val body = response.body()!!.string()
+                    if (response.body != null) {
+                        val body = response.body !!.string()
                         if (body.contains(REDIRECT_URL1) || body.contains(REDIRECT_URL2)) {
                             status.isInnerNet = true
                         }