Are you attempting to connect via that port remotely (outside your home network)?
If this is so, you will need to set up port forwarding on your router to forward anything coming in via port 55556 to go to your PC's private IP address (eg. 192.168.x.x).
For a step-by-step guide, look up your make and model of your router on
PortForward.com on how to forward ports for your router.
What software firewall are you using?