Friends can't join my server??

I have a Mac and my one friend has a PC and anytime we go to play GArry’s mod together she can’t join my games and I even went and forwarded the ports that it said to forward and nothing… Any suggestions???

Do you mean when you create a listen server they cannot join, or is it happening on every server you join?

If your trying to host a listen server and they cannot join try the following,

Double check the ports, make sure they are opened correctly (sometimes its the small thing you forgot to do). Use a site like http://canyouseeme.org to check if the port is opened.

Another common mistake people do is give their local IP, which cannot be accessed from outside your local network (192.168.x.x) instead of their WAN IP (The IP assigned by your Internet Provider). Use a site like http://ipchicken.com to find your WAN IP and give it to your friends. They can either add your server to their favorites list or they can use the connect command in console.
When your friends try to join you when your on a local server via their friends list (Steam friends) it will attempt to connect them to your local ip instead of your WAN ip)

Now if your friend is trying to join you on another server, one your not hosting you could try giving them the ip of the server your on and have them connect manually instead of them trying to join from their friends list… Not sure why you would have to as long as your connected to a server it’s able to resolve the ip from it should work fine… but who knows.

Hope this helps some…hope I did not confuse you more.