A connection to the VAC servers could not be made

When im playing a server and after about 1 minute i dissconnect and it says A connection to the VAC servers could not be made and it links me here https://support.steampowered.com/kb_article.php?p_faqid=374#connection. Also the toybox isnt working. This affects only garrys mod. I tried: Deleting clientblob, deleted local garrys mod files, restarted. How can i fix this?
Me and by bro live house but it hasnt made any problems untill today. Help!

Link me to your steam account.