The dashboard is a default place where all users are being redirected. When you redirect a user from http://smsapp.dvz.digital/ to Vanguard's login page, you provide the redirect page via $to parameter. However, if a user clicks the "Sign Up" link it will take him to a Sign Up page and it will loose the "to" URL parameter.
There are two ways to handle this:
1) If you want, you can customize the default redirect page inside the handleUserWasAuthenticated method in "app/Http/Controllers/Web/Auth/AuthController.php" file, and replace
return redirect()->to('your custom URL here');
2) You can modify how Vanguard redirects work and instead of looking for the "to" parameter during the redirect in "handleUserWasAuthenticated" method, you can store that parameter into the session when login page is rendered ("getLogin" method) and then pull it from the session in "handleUserWasAuthenticated" method.