"Video cache has stopped because there is not enough storage space. You can enable Auto Cache Clear or manually delete cache to get enough space"

Video cache is a low-resolution version of the video that is captured by the drone's camera. The video cache is stored on your phone/tablet.

This notification is letting you know that video cache will no longer be stored on your device until you clear the old cache or adjust the settings.

You can typically set how much video cache you would like to store within the settings section of the flight app. Additionally, you can choose to have the app automatically clear the old cache.