this thread helped me solve my problem, particularly the antivirus solutions of the original post:
" Also read for those with COMODO Antivirus, which I do not have, but I do have the Firewall to go to: Settings > Advanced Protection > Miscellaneous > Don’t detect shellcode injections in these applications. I’ve added the game folder “Call of Duty Modern Warfare”"
& this one for the sophos antivirus in one of the comments
“I just go to the help of the client app and choose help → troubleshooting → Local Exclusions… If I do it on the cloud for some reason dont work…”