No response yet, thanks. I've now sent two. Today, the symptoms changed. I signed out yesterday because I blew away all my cookies and local storage for Medium, and the sign in page didn't load after I did that.

Today, the signin page loads, but when I run it, the email authenticator hangs with the spinning box after I confirm my email. A lot of times when an authenticator displays a spinning icon or whatever hangs in the UI after an authentication process, you can navigate away and then just try a new page, because you're authenticated, because it was just a UI bug not handling the callback correctly. This is not the case here. I remain signed out on Chrome.

So that was my second ticket. I looked at the network tab in my Chrome dev tools and didn't see any http errors like a 503. I didn't dig deep, though, through all the responses, since I'm not paid to debug Medium, lol.

It works in Safari, which is a Chromium-based browser.