Unity launch screen is failing (multiple 2018.x versions)

This just started happening today, and it’s with two different versions of Unity that I have installed, so I have a feeling it’s failing to communicate with a server. It’s preventing me from working.

See video of whats happening at launch:

I disabled wi-fi, then launched again. It gave me the option to work offline. Quit the launcher, re-enabled wi-fi, launched. Asked me to sign in. After each sign-in, it now keeps going back to the sign-in screen.

This mysteriously started working again when I tried signing in just now. I really wish Unity would acknowledge these mysterious server issues.