I am trying to send one time password to a user using SMS INDIA HUB API. For that purpose I need to redirect to a URL format:
http://cloud.smsindiahub.in/vendorsms/pushs
Also, adding class
      use Illuminate\Http\RedirectResponse;
and after, like this:
 public function show($id){
    $link = Link::findOrFail($id);  // get data from db table Links
    return new RedirectResponse($link->url);  // and this my external link, 
 }
or -
 return  new RedirectResponse("http://www.google.com?andParams=yourParams"); 
For external links have to be used full URL string with 'http' in begin.