We've been having problems with Missive disconnecting from our IMAP mail server. The way Missive currently works is that only original account from which the connection to mail server was set up gets notified with the "Email account revoked" yellow strip at the bottom of the screen.
Since that account isn't being used by anyone (when I was setting Missive up I thought there should be the master (company) account and separate users' accounts), we don't know we're missing emails until we look into another email client.
I've assigned my user account to be the "owner" in the meantime, but still only the original account gets the yellow bar notification.