Laravel HTTP status code "1" is not valid error

I'm trying to access my url at: http://localhost/app/public/questions/1

My Routes

 $this->get('/questions/{question_id}','questionController@show');

My controller

public function show($question_id) {

    $showQuestion=questions::findOrFail($question_id);
    return redirect('questions',compact('showQuestion'));
}

For some reason I'm getting this error

InvalidArgumentException in Response.php line 458:
The HTTP status code "1" is not valid.

What could be the problem?

via Chebli Mohamed