Something (possibly Dovecot) broken after update

I just updated my MIAB setup, and immediately began recieving this error message:

The only non-green status checks are the one about password-based login through SSH, the one reminding me to setup Reverse DNS for IPv6, and one asking me to make a DS record. I’ve restarted MIAB and my server, to no effect.
I’ve tried a few of the solutions Google suggests (restarting Dovecot, deleting corrupted Dovecot files, etc.) This also didn’t work. Can anybody help me get it running again?
Edit: Now it’s working after restarting my computer? Maybe something to do with my login token? I’m baffled. But I guess, now I know?