There are several reasons this might happen. Obviously the biggest possibility is that you missed something when setting up your firewall or router. If you can tell us more about what you tried, in detail, that would help.

It's also possible, but less likely, your ISP is blocking the port upstream.

It looks like your Windows firewall is probably fine. The issue appears to be that you handled port forwarding incorrectly.

The screenshot you posted shows that there are two places to set up this sort of thing: The first part of the page is for port forwarding, and the second is for port "triggering"--which is a different thing. You need to set up your port for BYOND in the first section, not in the port triggering section.

If you're looking at the router's settings, there should be a way to change them.