People can't connect

Other people can not connect to my gmod server. And it is portforwarded.

Did you set the port in a bat file?(Im not sure if it should be in the bat file but in some script its either in the bat file or somewhere in the servers cfg map)

No I didn’t. I don’t even have a bat file.

Is this a dedicated server or are you creating it through Garry’s Mod? Make sure your port is actually unblocked here: http://www.canyouseeme.org

Can you post a screenshot of your port forwarded? Do you host from the same computer you play from?

Yes, http://imgur.com/BESqvPG

That’s probably why. Port forward port 27016 to TCP only – UDP isn’t used for SRCDS servers. Also, put -port 27016 in your server’s startup.bat.