getAccessToken() must be of the type string, null given

[Jonathan Stoker]

After login i'm getting redirect and the url is perfect containing an oauth_token, but i keep receiving the following error in production:

Argument 1 passed to Atymic\Twitter\ApiV1\Service\Twitter::getAccessToken() must be of the type string, null given, called in /var/www/laravel/routes/web.php on line 56

On local machine it works perfectly.