We are aware of the issue. We believe it to be a browser cache issue.
Here is an entire website dedicated to teaching people how to clear it. Please try the instructions and let me know if it fixes the issue. Browsers are sometimes suborn. Ive tried the login on Chrome and its now working. We had an issue yesterday that had caused the 502 and now the browser just responds to that. I believe it may fix the issue.
https://www.refreshyourcache.com/en/home/