When you launch the game, the following notifications are popped up on the screen. 

1. Recommended settings updated

2. Set optimal settings?

3. GPU driver version

In all cases click "No" and wait until the game starts loading. (Take a look at the screenshots) 

Loading shaders

If you see the process of loading shaders, as it's shown on the screenshot,  you can and should pause this process since it merely doesn't affect your gameplay. 

Choose any Warzone mode you are about to play, then click "Pause installation".

Pause installation

Unable to access online services

If you notice the next startup issue: "Unable to access online services" as shown below, keep in mind that this happens occasionally and you just need to reload the game from the launcher without closing your current game session.

Update requires restart

The notification below: "Update requires restart" stipulates that you just need to click "Exit" and the game will restart normally.