(See the best response by Kozuma3.)
Firewall: Exception made
Antivirus: No issue
Port forward: Port set and active but not allowing....
Details: missing entirely.
Screenshots: potentially helpful.
Best response
Lummox: Savage
Kozuma3: Sucking up to the big man
More information
is needed.
I have the same problem, I opened up the port to UDP and TCP... But my server still says BYOND hub reports port 53946 cannot be reached by players.

Also How would I setup byond via Console commands on a dedicated server.... or via TCADMIN Control Panel?
BWF, are you sure your port forwarding is going to the right machine?

A lot of routers now have the ability to permanently assign a particular local IP address to a certain computer on your network based on its MAC address. If you don't set that up, and the router reboots at any point, it's possible your computer simply changed local IPs and then the port forwarding that once worked doesn't work any longer.