Hello, this morning I've launched the Cu2 setup on my Exchange 2103 Cu1 Server (single server on W2012).
The prereq check told me that I had to remove non-US language packs, so I canceled the setup.
I restarted the transport service. About 30 minutes later, users started reporting that the mail flow was broken: we couldn't receive or send mail.
After some checks, I discovered that the server is no longer accepting connection on port tcp 25 and the only queue visible in queue manager is the submission queue.
Trying to telnet exchange server on port 25 tcp fails, the server immediately closes the connection.
I don't know how to restore the transport server functionality.