We have an Exchange 2013 server which was working fine, but after a failed CU2 upgrade, we rolled back to the restore and since then mail isn't flowing. All emails go into drafts.
We can telnet to port 25 locally on the server, but not from anywhere else, the connection is cut remotely.
There is no AV, nor any firewalls in the way. Servers in the same subnet are unable to connect on port 25...but can connect on port 80 for example, or 2525.
We've restored from various backups...all the same. Running out of ideas...
All thoughts very welcome.