We were using our MDaemon email server on Windows Server 2003 for years without any issue. Since a few days, the IMAP server suddently stop and gave us one error message:
Winsock Error 10013 Permission denied
After a few investigation on Google we found that the port is locked by "something".
So, we changed the classic 143 to a random port (500) and everything worked fine!
After a few tries, we found that telnet xxxxxx 143 give us the answer that the port is OK
* OK [CAPABILITY IMAP4 (...)]
So is this message normal or is that an issue?
How is that possible to find the running software that block us to connect to port 143?
Thank a lot for any help.