Hi, Richard. Thanks for the reply.
Yes, I believe all those bases were covered. The error happened literally minutes after creating the custom app. And the owner checked every box, giving it all scope permissions. And I believe all the points in the second note are done correctly.
However, I do have a question about this:
Permissions: Verify that the custom app has been granted the necessary permissions to access the data you’re trying to retrieve.
When the custom app was created there was no step done to grant any permissions (nor was there any in the instructions). The person who created the app was the owner of the site, so presumably he had full permissions.
Was there another step needed to explicitly grant the custom app permissions, apart from checking the boxes to specify the scope?
Thanks!
Neil