3CX have to find the IVR. He lost it because you changed the network adapters. The old details are still in the DB I think so maybe the most simple way is to uninstall and reinstall 3CX in the "new" environment instead of letting it work with different network adapters. Do a clean install with the backup and see if things change. When you use different subnets, you can read in the technical manual how to configure that