Hey there!
The solution: is to set up a startup for Battle.net Launcher.exe as an Administrator.
That’s it.
Explanation:
This will work if you do not have other problems. So before applying this solution do the Scan & Repair stuff.
Why this is happening?
As a part of windows’ optimizations to run the game with higher fps I have set up a ModernWarfare.exe to startup as an Administrator. The last patch applied not only to Warzone but to Battle.Net as well will prevent Battle.Net to Run a program with administrative privileges if the Battle.Net itself wasn’t started with the same level of administrative privileges. That’s the issue.