The free boost ads on level retry screen and the free lives ads both require a strong internet connection to work. It is normal to not receive an ad on every retry, as you might not have a strong enough connection or there might not be an ad ready to be served at all times. Additionally, the free lives videos can be watched only once a day.
In case you are unable to see any ads in the game, we recommend the following steps to see if they help:
- Force close the game, then launch the game again
- Try another connection, preferably Wi-Fi
- Restart your device