Laravel 2FA error

[dexterperalta121209]

why is it returns like this where i click complete registration? i checked the route and the code but it seems it didn't go through the controller. can anyone help me im stuck

    public function register(Request $request)
    {

if(DB::table('users')->where('student_no', '=', $request['student_no'])->exists()){
    $user = User::where('student_no', '=', $request['student_no'])->first();

    return back()->withErrors(['message' => 'student number is already taken ']);

}else {

    //Validate the incoming request using the already included validator method
    $this->validator($request->all())->validate();

    // Initialise the 2FA class
    $google2fa = app('pragmarx.google2fa');

    // Save the registration data in an array
    $registration_data = $request->all();

    // Add the secret key to the registration data
    $registration_data["google2fa_secret"] = $google2fa->generateSecretKey();

    // Save the registration data to the user session for just the next request
    $request->session()->flash('registration_data', $registration_data);

    // Generate the QR image. This is the image the user will scan with their app
    // to set up two factor authentication
    $QR_Image = $google2fa->getQRCodeInline(
        config('app.name'),
                    $registration_data['email'],
                    $registration_data['google2fa_secret']
    );

    // Pass the QR barcode image to our view
    return view('google2fa.register', ['QR_Image' => $QR_Image, 'secret' => $registration_data['google2fa_secret']]);



}
}

 public function completeRegistration(Request $request)
 {

// add the session data back to the request input
$request->merge(session('registration_data'));

// Call the default laravel authentication
return $this->registration($request);
}

Route

    Route::get('register', 'RegisterController@showRegistrationForm')->name('register');
    Route::post('register', 'RegisterController@register')->name('register.post');
    Route::get('/complete-registration', 'RegisterController@completeRegistration')->name('complete-registration');

when i click complete registration button it just redirect to a blank page with only a json response