If the wifi connection is lost, this guide explains how the wifi can be recovered. The wifi connection can be lost, if there is for example a blackout on a vessel.
How to set the portal into online and offline mode.
How to hard stop and start the portal app again. A hard restart, can help stuck entries to sync again. If a hard-reset does not help, temporarily setting the tablet to online mode can help, as explained in the other guide.
If the tablet is not reacting anymore, this guide explains how to perform a hard restart of the entire tablet to restore its functionality.
This guide explains how to resolve the "Location permission is required to get wifi name" error that appears when the app has no location permission.