SMTP Relay to Remote Active Directory Site.” and the last error is 451 4.4.0 Primary Target IP address responded
I have two sites both on Exchange 2010, both on Windows 2012 R2. I've attached a screenshot of what I am seeing in the queues from Site B to Site A. Port 25 is definitely open. I can telnet. I have restarted both servers. So I don't understand what on earth is going on and why these queues are occurring.
I read that it could be self signed SSL related? So I've tried re-applying the SMTP service to the current certificate and restarted the Transport services, but still these queues remain.
II'm trying to do Telnet sessions on both Site A and Site B. I am at Site A and Site B is where I took the snapshot of the queues from. I keep getting 'Unrecognized command' at both sides when I get to the part where I am supposed to enter 'ehlo server_name'. Once I try again, it goes to the next bit. I'm not mistyping anything either. I get to the part of the body and after I enter the '.' and hit enter, nothing happens. This is on both sides. Bizarre.