Intent call action doesn't work on Marshmallow

I'm trying to start a call intent action on a device who has Marshmallow as OS, Using the same steps as usual (This is working on versions below):

Add permission:

<uses-permission android:name="android.permission.CALL_PHONE" />

Open the intent:

Intent intent = new Intent(Intent.ACTION_CALL);
                    intent.setData(Uri.parse("tel:" + getString(R.string.connect_phone)));
                    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                    startActivity(intent);

This is the log I'm getting:

FATAL EXCEPTION: main

Process: com.app.calling, PID: 4250 java.lang.SecurityException: Permission Denial: starting Intent { act=android.intent.action.CALL dat=tel:xxxxxxxxxxxxx flg=0x10000000 cmp=com.android.server.telecom/.components.UserCallActivity VirtualScreenParam=Params{mDisplayId=-1, null, mFlags=0x00000000)} } from ProcessRecord{1618b01 4250:com.app.calling/u0a234} (pid=4250, uid=10234) with revoked permission android.permission.CALL_PHONE at android.os.Parcel.readException(Parcel.java:1620) at android.os.Parcel.readException(Parcel.java:1573) at android.app.ActivityManagerProxy.startActivity(ActivityManagerNative.java:3130) at android.app.Instrumentation.execStartActivity(Instrumentation.java:1540) at android.app.Activity.startActivityForResult(Activity.java:4283) at android.app.Activity.startActivityForResult(Activity.java:4230) at android.support.v4.app.FragmentActivity.startActivityFromFragment(FragmentActivity.java:849) at android.support.v4.app.FragmentActivity$HostCallbacks.onStartActivityFromFragment(FragmentActivity.java:907) at android.support.v4.app.Fragment.startActivity(Fragment.java:919) at com.app.calling.activity.fragment.ConnectFragment$2.onGroupClick(ConnectFragment.java:44) at android.widget.ExpandableListView.handleItemClick(ExpandableListView.java:676) at android.widget.ExpandableListView.performItemClick(ExpandableListView.java:654) at android.widget.AbsListView$PerformClick.run(AbsListView.java:3821) at android.widget.AbsListView$3.run(AbsListView.java:5841) at android.os.Handler.handleCallback(Handler.java:739) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:158) at android.app.ActivityThread.main(ActivityThread.java:7224) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

Again, this process is working fine in the previous version (Lollipop and kitkat)unfortunately isn't on Marshmallow, does anybody know why or what I'm missing?

Method to make call

public void onCall() {
        int permissionCheck = ContextCompat.checkSelfPermission(this, Manifest.permission.CALL_PHONE);

        if (permissionCheck != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(
                    this,
                    new String[]{Manifest.permission.CALL_PHONE},
                    "123");
        } else {
            startActivity(new Intent(Intent.ACTION_CALL).setData(Uri.parse("tel:12345678901")));
        }
    }

Check permission

@Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {

            case 123:
                if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {
                    onCall();
                } else {
                    Log.d("TAG", "Call Permission Not Granted");
                }
                break;

            default:
                break;
        }
    }