Can't join the server.

[Weecow]

Try to turn off vsync in you video options menu and delete unnecessary addons. If that doesn't work put -dxlevel 80 in you launch options.

And if it still doesn't work, follow these steps

Spoiler :

Please exit Steam and go to the folder called C:\Program Files\Steam\ (this is the default location for a Steam installation - if you set a different installation directory, you will need to browse to it).

Delete all of the files in this folder except:

The \Steamapps\ folder and Steam.exe (this file is listed as an application and features the black and white Steam logo)

Restart your computer.

Then, launch Steam.exe from within the Steam installation folder, and not from a pre-existing shortcut.

With Steam running, re-test the original issue.

Note: This process will not affect your currently installed games.

If the issue persists, make sure your network is optimized for Steam:

[Kwikee]

Are you by any chance from South Africa? If so I am too, I also cannot connect but if I go onto a VPN I can connect just fine. Maybe the server has some country's blocked?

[TylerSparks]

I actually just MIGHT have figured it out. My router has been blocking a lot of websites and stuff like that. One of the people that work for our ISP came down to our house to fix the internet and they replaced the router with a old used one like 2-3 months ago and it blocks, Xbox Live, Play Station Network, Reddit, sometimes google, and many other sites. I went and got a new router and it fixed those problems. That might have been the problem?
I am going to test it. I will edit the post after I finished to see if it worked.
*FIXED*

[Weecow]

Good to see you fixed it. See you on the servers again.

[zedzdead]

Servers are down once again. Good luck trying to join any time soon.

[Enzyme]

Problem fixed.

Closing.