app did not load successfully. Please contact the app creator / Appsheet database not found

[V-A]

After enquiring with AppSheet email support to troubleshoot another problem, I was advised to reconnect my app's tables with its database.  This resulted in the app no longer working and giving an error: 

The [X] app did not load successfully. Please contact the app creator.  Unable to fetch app definition. Error: Data table '[Y]' is not accessible due to: Requested item from AppSheet database not found or data may have been deleted.

The database and its tables' names haven't changed and the database now shows that it's no longer connected to any apps.  I've had this problem once before and had to build a new app from scratch because I couldn't get the app to reconnect with the database.

I've tried logging out and clearing the browser cache and haven't been able to fix this.  I also get the same error with different browsers and on different platforms, i.e. mobile and desktop.

I don't know if it's my settings or an AppSheet database bug, since the database feature is in a preview state (as someone stated recently in this forum regarding another problem).

I'd appreciate advice for troubleshooting this problem.

[V-A · Accepted solution]

Removing entirely, rather than reconnecting, all the app's tables linked to that database and then reloading the database and its tables seems to have resolved this.  The UX settings, virtual columns, and certain other settings were lost in this process so making a temporary copy of the app before removing the app's tables helped in recreating those settings once the source tables were relinked.

[Steve]

AppSheet Database is currently a preview feature and under active development. Preview features are not yet suitable for use in important apps. Until it has achieved greater stability, I recommend against using this preview feature except for testing and to help the AppSheet developers in their efforts. To follow the progress of and contribute to the development effort, please visit this dedicated Community topic:

Introducing new AppSheet database feature ...