Some feedback - I’m sure I hit this issue approx 19th Sep onwards (initially misdiagnosing as was unaware of this topic/report).
I have no idea of GitHub status over this period, but maybe someone can check that, as I see this issue goes back to August uptime/downtime events.
On the latest rebuild as of yesterday but existing admins can not log in.
Which is a weird state to be in, a ship without a captain but passengers and maybe no crew.
I was thinking as I was writing this reply, maybe if I create a new admin using rake command it might work, and guess what, it did!
So what is occurring here now is a historical admin is trying to log in and is getting the “Oops…” screen every single time, but a fresh admin user has no login access issues.