Veeam Can't communicate w/ prod vcenter if DR DC is offline

[dramos31]

I have a DC in my DR environment that is going to be decommissioned and when I turn it off to test if anything is affected Veeam cannot communicate with the Vcenter server.
The interesting thing is that the Veeam server is not even connected to anything in that subnet. I have tried uninstalling Veeam and reinstalling it. I have removed the Vcenter servers from the domain and added them back in. I do not see any mention of the DR DC anywhere on the Veeam Setup or in the host files.
I am going to demote the DC this week and then reinstall Veeam and see if that works. Any suggestions?

[Gostev]

DNS issue?

[dramos31]

Could you elaborate please? Is there anything in particular I should look for?

[Gostev]

I am just guessing that DC may be running AD-integrated DNS server.
When you turn it off, name resolution is no longer possible on your network.
So applications can no longer resolve DNS name to IP address when connecting to a server.

[dramos31]

I can look and see if that is the case. This particular DC is not the primary DC and sits on a different subnet. So it puzzles me that it would affect the production side vcenter server