When the video button is not available in the game, it could mean:
  • that the third-party video providers have run out of videos to play on your device. The providers continuously add videos, and the amount of videos available changes according to devices and user's geolocation.
  • you are experiencing a visual glitch. Simply force-close the game and re-open it and the videos should re-appear.
If videos are unavailable, you can still earn Diamonds by tapping the "Diamond" button in your Garage. Once tapped, you should see this pop-up:

You can tap this button 10 times to earn 10 Diamonds per day. Once all 10 have been earned, this pop-up will appear:

Please note, this method only works for watching ads for Diamonds. Watching ads for fuel and in Spoils of War still won't work.