ACS - Secondary linking errors

[DLCushion]

I am trying to repair a broken ACS Secondary configuration.  I currently have 2 primaries and want to make one of them a secondary.  These devices (virtuals) are both on the same version (5.8.1.4) and the same build.  They also have unique licenses.

When I try to send the request from the "secondary" server to the primary, I get a "Failed to lookup remoteHost" error and the secondary will not register.  I've made sure that DNS is reachable and that both devices are in the same domain.

What else would be causing this issue?

Thanks in advance for any leads!

[DLCushion · Accepted solution]

This is resolved.

I was given this system after it had broken, so presumptions were made about the previous state.

Found out someone made a change to the network - told no one - and broke the connectivity.