DirectX Error Fix
This error is common for players who are running older GPUs that do not support the new Windows 10 DirectX. However, players running newer GPUs are also reporting this error and hence it is not just limited to older GPU users. This is basically a technical problem and will only be properly fixed until Activision rolls out a patch with the fix. However, all is not doom and gloom for you because you can still try a workaround that has been working for a majority of players out there.
Start the game and head straight to the graphics settings. You need to make sure here that your game is not running at its maximum settings even if your PC is completely capable of running the game at maximum graphics. Lower down a bit and then quit the game. Go to Nvidia Control Panel, click Manage 3D Settings and then choose Program Settings. Choose Call of Duty: Warzone and the set Vertical Sync to ‘Adaptive Half Refresh-Rate’. Now go back to the game and graphics settings. Disable the V. Sync and now the game will run at flat 30FPS.