https://steamhost.cn/steamcommunity_com/discussions/forum/9/4691154661545105797/

Spam is not a solution for this either.

You don't need to spam discussions, Just one post was enough.

This is NOT a VAC Ban so you don't need to worry about anything.

- https://www.esports.net/wiki/guides/vac-was-unable-to-verify-your-game-session/
- https://www.makeuseof.com/windows-steam-vac-unable-verify-game-session/
- https://steamhost.cn/steamcommunity_com/discussions/forum/9/2828702372991195767/

A quick google search for that exact message brings up a lot of websites detailing some solutions. Hopefully you find something that will solve it.

The Steam discussions aren't the appropriate place to dispute specific bans, please read the following FAQ