diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index df943ec..56c839b 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -16,6 +16,7 @@
 
     <application
         android:allowBackup="true"
+        <!-- <to avoid java.io.IOException: Cleartext HTTP traffic to * not permitted> -->
         android:usesCleartextTraffic="true"
         android:icon="@mipmap/ic_launcher_square"
         android:label="@string/app_name"
diff --git a/app/src/main/java/com/team/focus/MainActivity.java b/app/src/main/java/com/team/focus/MainActivity.java
index 9174b7a..b3546c4 100644
--- a/app/src/main/java/com/team/focus/MainActivity.java
+++ b/app/src/main/java/com/team/focus/MainActivity.java
@@ -2,6 +2,7 @@
 
 import android.content.Intent;
 import android.os.Bundle;
+import android.os.StrictMode;
 import android.view.View;
 import android.widget.TextView;
 import android.widget.Toast;
@@ -23,6 +24,12 @@ public class MainActivity extends AppCompatActivity {
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
+
+        // to avoid "android.os.NetworkOnMainThreadException"
+        // https://stackoverflow.com/questions/6343166/how-to-fix-android-os-networkonmainthreadexception
+        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
+        StrictMode.setThreadPolicy(policy);
+
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         BottomNavigationView navView = findViewById(R.id.nav_view);
diff --git a/app/src/main/java/com/team/focus/data/pipeline/BackendUtility.java b/app/src/main/java/com/team/focus/data/pipeline/BackendUtility.java
index deb811d..49bb582 100644
--- a/app/src/main/java/com/team/focus/data/pipeline/BackendUtility.java
+++ b/app/src/main/java/com/team/focus/data/pipeline/BackendUtility.java
@@ -19,7 +19,11 @@ public class BackendUtility {
 
     // Backend URLs
 
-    private static final String HOSTNAME = "http://127.0.0.1";
+    // https://developer.android.com/studio/run/emulator-networking
+    // use 10.0.2.2 if running on Android emulator:
+    private static final String HOSTNAME = "http://10.0.2.2";
+    // use 127.0.0.1 or localhost if running on Android cell phone
+    //private static final String HOSTNAME = "http://127.0.0.1";
     private static final String PORT_NUM = "8080"; // change it to your mysql port number
     private static final String PROJ_NAME = "Focus";