Firebase Phone Authantication IOS (Ionic/Cordova)

Guys help im having problems with firebase phone authantication on IOS
The Code Below Works fine in Android but on IOS after recieving the code when i ckick verify im getting an Error in Xcode sayin " first argument vericationId must be a valid string"

PhoneLoginNative(phoneNumber) {
    this.FireBase.verifyPhoneNumber(`+${phoneNumber}`, 60)
      .then((credential) => {
        console.log("llllll" + credential);
        this.verificationId = credential.verificationId;
        this.showCodeInput = true;
      }).catch((error) => console.error(error));

  verify() {
    let signInCredential = firebase.auth.PhoneAuthProvider.credential(this.verificationId, this.code);
    firebase.auth().signInWithCredential(signInCredential).then((success) => {
      console.log("iddd" + success);
  presentAlert(id) {
    let alert = this.alertCtrl.create({
      title: id,

      buttons: ['Dismiss']

Did you fix it now?