Welcome to the Auth0 Community!
I do suggest that you attempt to access to /logout endpoint of the tenant and then try to log in once again. You can do this by going to https://[tenant-name].[locality].auth0.com/logout → as an example, if the tenant would be in the US zone and named test, the URL would translate to https://test.us.auth0.com/logout
In addition, this could be a caching issue and I suggest clearing the cache data just in case it might be affecting the authentication process. Leaving instructions as they might be useful:
- Google Chrome : Clear cache & cookies - Computer - Google Account Help
- Safari : Clear cookies in Safari on Mac - Apple Support (SA)
- Firefox : How to clear the Firefox cache | Firefox Help.
Looking at our Status page, there does not seem to currently be any service disruption or outage, so hopefully this is not a wide-spread occurrence.
Let me know if this helped you regain access!
Have a great one!
Gerald