Hi! Thanks for the extra information.
500s due indicate a server error, but I just tried and was able to authenticate, and no other reports of issues.
So, the server's up and working.
500's can be caused if a local or gateway firewall on your end, including extensions, change or block any packets or headers, causing a malformed request. This should be caught on our end ideally, but as this authenticator isn't that robust it isn't.
Adding it manually may cause issues, but I don't think so.
Can you attach a screenshot or two after doing a do a hard-reload: use Chrome, open its devtool's Console, ensure XHRs are logged, and provide a screenshot of your entire browser. I can explain that more if required!
Have one to start with when you get the 500. Thanks, as that may start to shed some more light on what the issue is!