Yes, during the last update the admins revoked all the auth keys, forcing everyone to login again. There was some concern over security, related to the exploit that was used to compromise lemmy.world

Clearing cache & data should also allow you to re authenticate.

I had to re-login on voyager, my account had mysteriously disappeared from the app this morning.

I do wish there was a way for admins to send a notification to people when they revoke login tokens to avoid confusion. This will almost certainly happen again at some point.