Everything is working for me once again and I'm able to log in with all browsers. I'm not sure what server-side changes were made, as I didn't change anything. Perhaps the ones in this thread?
https://ledstrain.org/d/788-http-access-buggy/8
Any idea what may have been causing the "something went wrong" message? Were there non-SSL hops in the login traffic flow perhaps?
When this issue was occurring, the only method I had for logging in was using my iPhone 6S+ Safari browser, or an old IE11 browser on a Windows 7 machine. Maybe the only way of logging in before the fix(es) was using a browser that didn't really care about browser-based security =)