Garry's Mod server connection issues.

So, for about 10 days now, I have been unable to connect to any Garry’s Mod server. I called an ATT technician to come and replace my modem/router and he did, the issue is still arising.

This happens to any server I attempt to connect to, not any specific servers.

The issue is: I connect to the server and I load up, once I get to sending client information, it stays there for about 10 minutes and if I am lucky enough, I can get in the server for a second, but right after, Auto Disconnect appears. If I don’t even get into the server, after waiting 10 minutes on Sending Client Info, I get kicked for timing out.

I simply cannot find the issue with my computer or network and it is frustrating me.

Any suggestions are welcome.