When you use the interactive sign in with AD option with a SQL database, it's not very stable in it's connection. I suspect it's either not supporting the refresh tokens (if it has them) or hasn't got the right detection for an expired token.

When authentication fails in this mode, it gives up silently and functionality starts to turn off as it can't connect to the database - see attached log.

I have to close SSMS every 3 hours or so, which forces SQL prompt to re-authenticate and get a new token. Turning on/off suggestions does not trigger a reauthentication.