Can't join any server

I’ve got a problem with joining servers in Garry’s Mod. Whenever I attempt to join one, the game says that this account has been logged onto another computer and that I need to log into steam again, but I am already logged in and nobody else is using my steam account.

What can I do to fix this problem?

Log out and back into steam.

Yeah I did that, but that doesn’t work. That’s the whole problem, Garry’s Mod thinks I am logged out always, even when I’m really logged in. Team Fortress 2 or Shattered Horizon doesn’t give me any problem, so the problem is associated with Garry’s Mod.

I’m gonna delete local content and reinstall Gmod in that way. Hope it works.
If anyone knows this problem, any help is still very much appreciated.

[editline]12:54PM[/editline]

Deleting local content didn’t work.

It’s as if someone else logs in with my steam account just when I’m connecting, without me logging out in any way.

Im having the same problem can someone help me with it

Close steam and try deleting the file Clientregistry.blob from the steam directory, then start steam and try again