My smartermail server IMAP port 143 is not working. I also tried to open different port but still not work. i check my firewall rules and it is ok. i off the windows server 2012 r2 firewall but still no success.  I have enabled the IMAP port from smartermail admin > Settings > Branding > ports.

 

I also enable the IMAP port to IP address, from smartermail admin > Settings > Branding > IP Address.