It’s important that the Let’s Explore Oceans Holographic Explorer Cube and its markings are easily seen by your smartphone. Make sure you are using your cube in a well-lit location.
If you stop seeing augmented reality content layered on top of your Let’s Explore Oceans cube it may be that you are blocking too much of the cube’s markings with your fingers. Try repositioning your hand around the cube to block less of the cube from the phone’s camera.