diff --git a/android/build.gradle b/android/build.gradle
index 5a9971bf..736bb8e8 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.0.1'
+        classpath 'com.android.tools.build:gradle:3.6.4'
     }
 }
 
diff --git a/android/src/main/java/io/wazo/callkeep/RNCallKeepModule.java b/android/src/main/java/io/wazo/callkeep/RNCallKeepModule.java
index 3e90e349..1632fd6d 100644
--- a/android/src/main/java/io/wazo/callkeep/RNCallKeepModule.java
+++ b/android/src/main/java/io/wazo/callkeep/RNCallKeepModule.java
@@ -514,7 +514,9 @@ public void startCall(String uuid, String number, String callerName, boolean has
 
         Log.d(TAG, "[RNCallKeepModule] startCall, uuid: " + uuid);
         this.listenToNativeCallsState();
-        telecomManager.placeCall(uri, extras);
+        try {
+            telecomManager.placeCall(uri, extras);
+        } catch (SecurityException ignored) {}
     }
 
     @ReactMethod
@@ -532,7 +534,7 @@ public void endCall(String uuid) {
         }
         Context context = this.getAppContext();
         AudioManager audioManager = (AudioManager) context.getSystemService(context.AUDIO_SERVICE);
-        audioManager.setMode(0);
+        audioManager.setMode(AudioManager.MODE_NORMAL);
         conn.onDisconnect();
         this.stopListenToNativeCallsState();
         this.hasActiveCall = false;
@@ -675,7 +677,11 @@ public void checkDefaultPhoneAccount(Promise promise) {
         }
 
         boolean hasSim = telephonyManager.getSimState() != TelephonyManager.SIM_STATE_ABSENT;
-        boolean hasDefaultAccount = telecomManager.getDefaultOutgoingPhoneAccount("tel") != null;
+
+        boolean hasDefaultAccount = false;
+        try {
+            hasDefaultAccount = telecomManager.getDefaultOutgoingPhoneAccount("tel") != null;
+        } catch (SecurityException ignored) {}
 
         promise.resolve(!hasSim || hasDefaultAccount);
     }
@@ -1080,14 +1086,20 @@ public void backToForeground() {
         if (isOpened) {
             focusIntent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
             activity.startActivity(focusIntent);
-        } else {
-            focusIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK +
-                    WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED +
-                    WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD +
-                    WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
+            return;
+        }
 
-            getReactApplicationContext().startActivity(focusIntent);
+      focusIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
+            activity.setShowWhenLocked(true);
+            activity.setTurnScreenOn(true);
+        } else {
+            activity.getWindow().addFlags(
+                WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED +
+                WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
         }
+
+        getReactApplicationContext().startActivity(focusIntent);
     }
 
     public static void onRequestPermissionsResult(int requestCode, String[] grantedPermissions, int[] grantResults) {