SalesForce Integration Issue

So I’m a newbie to AppSheet. I built my first app using Cases and a custom object. Everythig was working great, but when I added two new fields to my custom object, I now get an error:
“Unabale to fetch app definition. Error: Object reference not set to an instance of an object.”

I then ran the “Regenerate Structure” on the data source and now the ‘View Columns’ tab is not even available. NO DATA AT ALL.

Has anyone else come across this issue? Is there a work-around?
I can’t imagine an app is going to break everytime a new field is added to a source object in SF.

I advise contacting directly for the issue.