What you're encountering is a technical limitation that we've placed on file storage in the database. While we don't impose any strict limits on the length of data that you can save to a database field, something that is extremely long (for instance: text-encoded images, base64 images, file URLs, or lists of things) can cause the corresponding database view to be inaccessible.

The solution here is to delete the database entry(s) that contain these long values, allowing your app data to function properly again. To do this, you'll want to create a new workflow to delete the entry with a unique ID referenced and attach this workflow to a button element that can be clicked in run mode.