Hey guys, I know I'm late replying but it happened to me and this is the first thread to pop up when searching the error.
How I fixed it is :
1. Make sure your NAT type is Open, I thought mine was but when I checked again it was strict! (Nat Type 3, plenty of tutorials on YT )
2. Install textures to HDD - I don't think this is important, but when I did it it worked.
3. Wait for about 2minutes, then go to "Options" and press the "Select" button.
4. Check your bandwith, it needs to be about 50kbps+
5. Join, try it about 3 times.
If this doesn't help sorry, but that's how I fixed it
I have a friend that has been banned. It will say, NOTICE:You are VAC Banned. YOU CANNOT PLAY ONLINE.
So, you just have something to tell Customer Support or email Valve about. Good news is YOU ARE NOT BANNED!
Strange how things don't work the way they are expected to when called perfect. Titanic sunk. Biggest example of an epic fail. 102 years of its creators being known as big jokes. He he.