i know that problem, it means.
1. your router is stupid
2. you need to in steam settings set a lower attempts per sec
3. your ISP is stupid
So, it isn't my gmod that is broken, it is my steam. (I know it's not my internet because my cousin in the same house as me was able to play multiplayer right next to me) but I tried playing a free multiplayer game (team fortress 2) and no servers were able to load either, said no servers meet my search criteria. So any fixes as to why no steam games can load multiplayer for me?
i know that problem, it means.
1. your router is stupid
2. you need to in steam settings set a lower attempts per sec
3. your ISP is stupid
Are you checking that there are no other programs maybe conflicting with Steam?
Do you have any foreign files installed into your GMOD directory? If so, remove them immediately.