sql-2016-alwayson - First SQL-Server throwing communication errors

Hi there,

we're currently trying to deploy sql-2016-alwayson on our lab-system. The deployment as it is, works pretty well but we're currently facing the issue that one of two SQL-Servers is throwing errors that the aoglistener and the aodns seem to be offline.
The other SQL-server doesn't throw errors and sees the aodns and aoglistener online.

Is it intended to work this way or did we missed out on something?

Best regards