I got the same message dude. I used the FoV changer once when the game first came out. Played around 3 matches then backed up the game, and uninstalled it for if they ever decided to fix the lag and add a proper FoV slider.
I re-installed it today and ran Dxtory to view my FPS in game. Played a few matches and got the same message as you. I tried about 3 times to get back on and managed to do so. I do not have a VAC bans on record and my ID seems clean.