Azure B2C new URLs Redirect Problem

Hi,
we use Azure AD B2C for authentication and due to the deprecation of the old URL format (login.microsoftonline.com) to the new URL format (b2clogin.com), we’ve updated all of our social login providers in our test system. It worked instantly with Google and Microsoft OAuth applications, but changing the Authorization callback URL to the new one in Github did not work.

The result is a 404 error on https://github.com/login/oauth/authorize. The redirect_uri parameter is correct and matches the one entered in the App registration.

Does anybody have any idea why it doesn’t work?

Thanks!