Internet Servers Counter Strike Source — Cd Key Authentication Invalid For

Your Steam account does not own a valid Counter-Strike: Source license for the version you’re trying to play. This usually happens with old retail (disc) keys or third-party keys.

FIXED: "CD Key Authentication Invalid" on internet servers (CSS) Your Steam account does not own a valid

If you bought a key from a third-party site (G2A, Kinguin, etc.) for $2, it’s almost certainly a stolen or region-locked key. Steam will reject it for internet play. Refund it if you can. etc.) for $2