Querying Contacts

Question:
I created a backend function to query Wix Contacts to create an HTML chart via front end code. Works great in test but in production I get “Error: Unable to handle the request. Contact the site administrator or view site monitoring logs for more information.”

Product:
Editor

What are you trying to achieve:
Displaying HTML chart on a page based on data in Wix Contacts.

What have you already tried:
Chart is done and working in test. But does not work in production.

Additional information:
Have many other charts on same page that work fine (not based on Wix Contacts data)

Maybe something related to the contact permission if others works well, contact is sensitive data in wix