Running on Windows 2012r2. I have a server running mta's and post offices. I also have a server running a GWIA in its own domain. This system cannot talk to any other servers and is running on VM's. The data from my live GW 2012 system was cloned and attached to the appropriate servers. I installed GW 2012 on the server using the data volumes to install to. It worked great. The system came up and users had all the email in their accounts that was there at the clone point. I upgraded the servers running the post offices to GW 2014. This went well. Email moves around in the system as it should. I then installed the GW 2012 gwia on the other server using cloned data. I had to make ip address changes in the whole system, but all works. I have double checked and triple checked the links and all seems good. The GWIA accepts email when I try to force an email to route out and back into the system. I am receiving a 450 host down when it tries to find the post office server. I have made sure all firewalls are off. DNS entries have been checked multiple times. I am overlooking something. Any help will be appreciated.