Exchange Server 2013 running virtualized on Server 2012 Hyper-V host. All services are running. No errors in the Event Logs. No mail is flowing internally or externally. Test-MailFlow shows failure when testing local mailboxes from the Exchange Server console. Outlook client cannot connect. Error is "421 4.3.2 Service not available".
MS will not assist using partner tech support events because Exchange Server 2013 is out of mainstream support.