diff --git a/testapps/ImsTestService/src/com/android/phone/testapps/imstestapp/ImsRegistrationActivity.java b/testapps/ImsTestService/src/com/android/phone/testapps/imstestapp/ImsRegistrationActivity.java
index 139f8ac..5c0416b 100644
--- a/testapps/ImsTestService/src/com/android/phone/testapps/imstestapp/ImsRegistrationActivity.java
+++ b/testapps/ImsTestService/src/com/android/phone/testapps/imstestapp/ImsRegistrationActivity.java
@@ -182,7 +182,7 @@
         try {
             mImsManager = ImsMmTelManager.createForSubscriptionId(
                     SubscriptionManager.getDefaultVoiceSubscriptionId());
-            mImsManager.registerImsRegistrationCallback(mRegistrationCallback, getMainExecutor());
+            mImsManager.registerImsRegistrationCallback(getMainExecutor(), mRegistrationCallback);
         } catch (IllegalArgumentException | ImsException e) {
             Log.w("ImsCallingActivity", "illegal subscription ID.");
         }