Request callback failed

My NextJS
app is running in an iframe. When I use the /api/auth/login request it works but the callback request fails.

The application is uploaded on Vercel, so the option that this is due to http on localhost is not suitable, the application uses https

Hi there @a.berdyshev welcome to the community!

Are you using New Universal Login or Classic? If Classic, have you tried toggling the setting mentioned here.

FWIW I have also seen this error arise due to config errors, so I would double check all config/environment variables in Auth0 as well as Vercel.

Hope this helps!