Bulk Edit works great in standard MS tenant, but fails in customer's tenant

I really like the Bulk Edit tool and have successfully installed and used in a Development tenant, which has default Microsoft configuration. Now we’re moving to an Acceptance Test tenant that the customer has set up and then it doesn’t work.

When I ‘Select Fields’, select a custom field and click OK, an error message is displayed in the bottom left corner: “Error loading page, error was: error details: Forbidden”.

Fields with a lookup table, don’t display the lookup values to be selected.

Then, after entering a valid value in a cell (instead of selecting it from the lookup table), an error message is displayed: “Last Error: The unable to update custom field: [fieldname] could not find field or unsupported field type.”

I’ve checked permission levels as described in this blog post: https://nearbaseline.com/2014/11/controlling-project-odata-permissions-for-apps-and-reporting/

Could you give any pointers to resolve this?

Thanks!
Bram