ID:1314746
 
(See the best response by DarkCampainger.)
So yesterday i hosted my game and there was no problem i even played with friends and today i am hosting it again but it says that the port is closed i have a PortChecker and there it says the port is open so i have no idea where is the problem :\
Best response
What's the exact error message? Did you previously port-forward that port on your router? Are you hosting on the same port? Is it possible your internal IP changed since when you port forwarded? If you updated BYOND and have a firewall, try removing any firewall rules for BYOND and letting it "relearn" to allow it.