Official comment
From the Terrain Awareness article:
"In order to be able to access the terrain data with Map Pilot, a valid Access Token must be entered in the settings. Think of an access token as a password that allows the app to download the data. Once terrain data is downloaded for an area it is available for offline flight planning."
https://support.dronesmadeeasy.com/hc/en-us/articles/211810943-Terrain-Awareness