Any ideas why Messages on my iMac would suddenly stop sending/receiving, but the iOS Messages on my iPad continues to send/receive using the same account? Both apps are set-up identically and are on the same home network. A big red ! appears next to anything I try to send, and I get the error "Your message could not be sent. Click “Try Again” to send this message.
Messages on my Mac says I'm available and my account is enabled.