We are currently using FreePBX version13 on a physical server which is running on its own VLAN. We are trying to retire an old Windows domain controller (All domain related features have already been removed) and when it is shutdown our desk phones go offline/no calls internal or external. When we turn on the server everything starts working again.
The odd thing is when the server is shutdown, the phone server does have connectivity to ping google, etc.
I have checked multiple services on the server and looked through the phone system for a connection but didn’t have any luck.
Phone system is not connected to AD
Any ideas of how the two are connected or anyone else have this issue?