Make sure you are signed into your Google account on your Android phone

To ensure Avenza Maps will operate, you need to be logged into a Google account in order to continue using the app. If you log out of your Google account, the Operating System will prevent the app from opening after a few days for safety reasons.

You need to be logged into a Google account since the app uses Google Play Services. Play services would not work properly if the user is not logged into a Google account.