Server is listening in Port 110 and I can't find any way to disable or block it
Solution 1:
Confirmed to be a "S-Box Security Internet Firewall" by tracing the traffic and connecting to every hop IP using telnet on port 110. All traffic on port 110 passing this device seems to be intercepted.
Solution 2:
You probably have firewall in between your workplace (where you were running scan) and your server. The simplest check would be to try connecting to said port for the machine itself:
telnet 123.123.123.123 110
If it doesn't connect, you are most likely OK.