Android.ConnectionService Incoming call UI not showing onShowIncomingCallUi

I am building basic calling app using TelecomManager, ConnectionService and Connection. But, When an there is an incoming call, my incomingActivity UI is not showing up. Below is the sample code so far.

In my MainActivity.java

Intent intent = new Intent(TelecomManager.ACTION_CHANGE_DEFAULT_DIALER);
intent.putExtra(TelecomManager.EXTRA_CHANGE_DEFAULT_DIALER_PACKAGE_NAME, getPackageName());

startActivity(intent);

// ================================================================
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    TelecomManager manager = (TelecomManager) getSystemService(TELECOM_SERVICE);

//            new ComponentName(getPackageName(), CallHandler.TAG), "myCallHandlerId");
    PhoneAccountHandle phoneAccountHandle = new PhoneAccountHandle(
            new ComponentName(getApplicationContext(), CallHandler.TAG), "myCallHandlerId");

    PhoneAccount phoneAccount = PhoneAccount
                            .builder(phoneAccountHandle, "myCallHandlerId")
                            .setCapabilities(PhoneAccount.CAPABILITY_SELF_MANAGED)
                            .build();

    manager.registerPhoneAccount(phoneAccount);

    Log.i("Phone Account", "" + manager.getPhoneAccount(phoneAccountHandle));
    Log.i("Phone Account", "" + manager.getPhoneAccount(phoneAccountHandle).isEnabled());
    Log.i("Phone Account", "" + manager.getPhoneAccount(phoneAccountHandle).getClass());

    Log.i("Phone Account isEnabled", "" + phoneAccount.isEnabled());

    Bundle bundle = new Bundle();

    Uri uri = Uri.fromParts(PhoneAccount.SCHEME_TEL, "555555555", null);
    bundle.putParcelable(TelecomManager.EXTRA_INCOMING_CALL_ADDRESS, uri);
    bundle.putParcelable(TelecomManager.EXTRA_PHONE_ACCOUNT_HANDLE, phoneAccountHandle);

    //            manager.addNewIncomingCall(phoneAccountHandle, bundle);

    Log.i("Permitted", "" + manager.isIncomingCallPermitted(phoneAccountHandle));

    if(manager.isIncomingCallPermitted(phoneAccountHandle)){
        Log.i("Call", "Incoming");
        manager.addNewIncomingCall(phoneAccountHandle, bundle);

    }
}

In my CallHandler.java

@RequiresApi(api = Build.VERSION_CODES.M)
public class CallHandler extends ConnectionService{

    public static final String TAG = CallHandler.class.getName();

    @RequiresApi(api = Build.VERSION_CODES.N_MR1)
    @Override
    public Connection onCreateIncomingConnection(PhoneAccountHandle connectionManagerPhoneAccount, ConnectionRequest request) {
        Log.i("CallHandler","onCreateIncomingConnection");

        //        return super.onCreateIncomingConnection(connectionManagerPhoneAccount, request);

        Context context = getApplicationContext();

        Log.i("Context","" + context);
        Log.i("Context","" + context.getPackageName());
        Log.i("Context","" + getBaseContext());
        Log.i("Context","" + context.getClass().getName());
        Log.i("Context","" + context.getClass().getSimpleName());


        CallConnection callConnection = new CallConnection(context);
        callConnection.setInitializing();
        callConnection.setActive();

        callConnection.setCallerDisplayName("Manik", TelecomManager.PRESENTATION_ALLOWED);
        //        callConnection.setConnectionProperties(Connection.PROPERTY_SELF_MANAGED);
        //        callConnection.setConnectionCapabilities(Connection.CAPABILITY_HOLD & Connection.CAPABILITY_SUPPORT_HOLD);


        return callConnection;
    }

    @Override
    public void onCreateIncomingConnectionFailed(PhoneAccountHandle connectionManagerPhoneAccount, ConnectionRequest request) {
        super.onCreateIncomingConnectionFailed(connectionManagerPhoneAccount, request);
    }

    @Override
    public void onCreateOutgoingConnectionFailed(PhoneAccountHandle connectionManagerPhoneAccount, ConnectionRequest request) {
        super.onCreateOutgoingConnectionFailed(connectionManagerPhoneAccount, request);
    }

    @Override
    public Connection onCreateOutgoingConnection(PhoneAccountHandle connectionManagerPhoneAccount, ConnectionRequest request) {
        return super.onCreateOutgoingConnection(connectionManagerPhoneAccount, request);
    }
}

In my CallConnection.java

@RequiresApi(api = Build.VERSION_CODES.M)
public class CallConnection extends Connection {

private Context context;

@RequiresApi(api = Build.VERSION_CODES.N_MR1)
public CallConnection(Context con) {
    context = con;
    setConnectionProperties(PROPERTY_SELF_MANAGED);
    setAudioModeIsVoip(true);
}

@Override
public void onAnswer(int videoState) {
    super.onAnswer(videoState);

    Log.i("Call","Answered");
}

@RequiresApi(api = Build.VERSION_CODES.O)
@Override
public void onShowIncomingCallUi() {
    Log.i("Call","Incoming Call");
    super.onShowIncomingCallUi();

    //        MainActivity con = new MainActivity();
    //        Context context = con.getApplicationContext();

    NotificationChannel channel = new NotificationChannel("channel", "Incoming Calls",
            NotificationManager.IMPORTANCE_HIGH);
    channel.setImportance(NotificationManager.IMPORTANCE_HIGH);
    // other channel setup stuff goes here.

    // We'll use the default system ringtone for our incoming call notification channel.  You can
    // use your own audio resource here.
    Uri ringtoneUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_RINGTONE);
    channel.setSound(ringtoneUri, new AudioAttributes.Builder()
            // Setting the AudioAttributes is important as it identifies the purpose of your
            // notification sound.
            .setUsage(AudioAttributes.USAGE_NOTIFICATION_RINGTONE)
            .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
            .build());

    //        NotificationManager mgr = context.getSystemService(NotificationManager.class);
    //        mgr.createNotificationChannel(channel);


    // Create an intent which triggers your fullscreen incoming call user interface.
    Intent intent = new Intent(Intent.ACTION_MAIN, null);
    intent.setFlags(Intent.FLAG_ACTIVITY_NO_USER_ACTION | Intent.FLAG_ACTIVITY_NEW_TASK);
    intent.setClass(context, IncomingCallScreenActivity.class);
    PendingIntent pendingIntent = PendingIntent.getActivity(context, 1, intent, 0);

    Log.i("Intent1","" + intent);
    Log.i("Intent2","" + intent.getPackage());
    Log.i("Intent3","" + intent.getType());
    Log.i("Intent4","" + intent.getData());
    Log.i("Intent5","" + intent.getDataString());
    Log.i("Intent6","" + intent.getAction());
    Log.i("Intent7","" + intent.getCategories());
    Log.i("Intent8","" + intent.getExtras());

    Log.i("Pending Intent","" + pendingIntent);
    Log.i("Pending Intent","" + pendingIntent.getCreatorPackage());

    // Build the notification as an ongoing high priority item; this ensures it will show as
    // a heads up notification which slides down over top of the current content.
    final Notification.Builder builder = new Notification.Builder(context);
    builder.setOngoing(true);
    builder.setPriority(Notification.PRIORITY_HIGH);

    // Set notification content intent to take user to fullscreen UI if user taps on the
    // notification body.
    builder.setContentIntent(pendingIntent);
    // Set full screen intent to trigger display of the fullscreen UI when the notification
    // manager deems it appropriate.
    builder.setFullScreenIntent(pendingIntent, true);

    // Setup notification content.
    builder.setSmallIcon(R.mipmap.ic_launcher);
    builder.setContentTitle("Your notification title");
    builder.setContentText("Your notification content.");

    // Set notification as insistent to cause your ringtone to loop.
    Notification notification = builder.build();
    notification.flags |= Notification.FLAG_INSISTENT;

    // Use builder.addAction(..) to add buttons to answer or reject the call.
    NotificationManager notificationManager = context.getSystemService(
            NotificationManager.class);
    notificationManager.notify("Call Notification", 37, notification);

    //        context.startActivity(intent);


    }
}

All the log messages inside onCreateIncomingConnection() and onShowIncomingCallUi() are showing up when the app launches, and not when there is an incoming call.

All the permissions in AndroidManifest.xml

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-html -->

<uses-permission android:name="android.permission.READ_CONTACTS" />
    <uses-permission android:name="android.permission.READ_CALL_LOG" />
    <uses-permission android:name="android.permission.WRITE_CONTACTS" />
    <uses-permission android:name="android.permission.CALL_PHONE" />
    <uses-permission android:name="android.permission.MANAGE_OWN_CALLS" />
    <!--
 Needed only if your calling app reads numbers from the `PHONE_STATE`
         intent action.
    -->
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".IncomingCallScreenActivity"></activity>
        <activity android:name=".CallScreenActivity" />
        <activity android:name=".ContactsActivity" />
        <activity android:name=".LogsActivity" />
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />
                <action android:name="android.intent.action.DIAL" />

                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE" />

                <data android:scheme="tel" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.DIAL" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>

        <service
            android:name=".CallHandler"
            android:permission="android.permission.BIND_TELECOM_CONNECTION_SERVICE">
            <intent-filter>
                <action android:name="android.telecom.ConnectionService" />
            </intent-filter>
        </service>
    </application>

<!-- end snippet -->

Any help would be appreciated. Thanks