Server Not Responding

Hey. I’ve been attempting to host a Garry’s Mod server, but for some reason, I can’t. I’ve opened my tcp and udp ports 27015-27016 on my router, did sv_lan 0, all that crap, yet when people try to join my server, they get a message that says server not responding. Ive given them the ip adress found on sites like ipcake follwed by :27015, still won’t work. They always get the server not responding message. Any help would be appreciated.

And before someone says it, YES, I’m SURE I forwarded my ports.