macOS! Matchmaking stops because software disturbs vac

Hello folks I have been playing CSGO on my iMac with the Catalina 10.15.3 software for months now without any problems.

Today for the first time I was kicked out of a match making with the error message that a software disrupts the Vac connection to steam.



What is it and how can I fix it and before someone screams ... no I have no cheat programs running