401 Unauthorized after login (Laravel)

Hi,

After successfully authenticating w/ Auth0 universal login, I get this error when I am redirected to the call back url. I am using Laravel 8.0. Can you help please? Thanks

GuzzleHttp\Exception\ClientException

Client error: POST https://appname.eu.auth0.com/oauth/token resulted in a 401 Unauthorized response: {“error”:“access_denied”,“error_description”:“Unauthorized”}

http://xxxxx/auth0/callback?code=J2n3zma7vAoLSwP8&state=2cbd42747203861f519fdc693910d8cb

Any help please? would try appreciate it. I am stuck…