Are your source servers not VAC secure all the sudden? It’s Steam’s fault.
If you’re playing happily on your server and it all the sudden starts complaining about your connection to steam servers being down, don’t panic… it happens to everyone. Steam has decided to do their regular past-time of sucking and caused their VAC servers to go down. When this happens, everyone’s server is unable to connect to VAC and verify and thus become insecure.
The only thing you can do to your CS:S, TF2, Insurgency or otherwise Half Life Source server is to restart it every 10 or 20 minutes until Steam comes back up.
It’s not our fault! 