Problem:

Functional apps change to Premium license and show the error message as below when you run it.

Solution:

Navigate to the connections pane in the editor and see what connections are being used in the app.

Turn off or remove all the Common Data Service (CDS) connector then your standard licensed apps will be work as normal.

Currently, within PowerApps, the user who own Office 365 Business, Office 365 Enterprise E1 or Office 365 F1 licenses could not use an app which includes a custom connectors or On-Premises data Gateway connection.