Hi, if anyone is still having this issue, this is what fixed it for me.
When you are on the Login page
Modify the URL by adding “0” right after “auth” so it looks like: https://auth0.openai.com//authorize?client..
reload the page by hitting enter when in the URL field, the page should now contain “0” in the URL and be reloaded, put in your email and the password prompt should show up allowing you to sign-in