Hey there,
Can you try the following steps and see if they help with the error :
- Run Battle.net app as admin (right click + run as admin
- Open the game directly from the install folder instead of using Battle.net App
- Delete Call of Duty folder in your Documents folder
- Remove any “command line arguments” you have set up for Call of Duty in the Battle.net App (Battle.net Icon > Settings > Game Settings > Warzone)
- Move game install to any different folder, then update file path in the App Battle.net Icon > Settings > Game Settings > Warzone)
Hopefully this should help!