Parkunload requires Internet access via mobile data or Wi-Fi to be able to communicate the parking stop order to the servers. Otherwise, it will not be possible to end the ticket manually and the ticket will be closed automatically.
If the smartphone does not have Internet access, it will not be possible to finish the parking session and the app will progressively notify you of the expiration of the parking session.
Remember that it is recommended to stop the parking session, but it is not mandatory and is not subject to penalties.
Note that parking tickets started via web form cannot be stopped.
See more information in Stop parking session