Steam Validation Rejected

[Zephos]

It seems everytime I try to connect to a Counter Strike Source server it comes up with "STEAM Validation Rejected". I validated the files and yet it stills come up with this...(I can connect to DoD: Source servers...but not CS)

 

[Beerdude26]

Oddness :|
Tried restarting your computer? Restarting Steam?

 

[Przemek]

Try typing in the CS:S console:
sv_Lan 1
and/or deleting (or modifying the sv_lan value to "1" in it) listenserver.cfg