When I open the battle.net app the games show up but the HTML does not load. It appears as code. This has never stopped me from being able to play games but with COD Cold War the Play button is not visible. I’ve tried to load the game from the program files without luck either. I have screen shots I can email.
The most common cause I see for the app encountering such behavior is Malware. Please be sure to run a full system scan as soon as possible. I normally recommend the free version of Malwarebytes if you do not already have a service for this.
Once you’re sure the system is clean, try troubleshooting security software. Even though it’s made to prevent unwanted activity it can also sometimes prevent wanted activity.
Let us know how things go. Cheers!