No preview access to G folder for non-admins

I have a setup with several G folders, with access by Admins and logged in users.
All has been working OK so far, with all users able to view, preview and download files.

I have now created a new file browser view with a link to pre-existing G folder and files. The admin can see the files in the lightbox, but no other user roles are able to view the files in the lightbox.
Error msg:
403. That’s an error.
We’re sorry, but you do not have access to this page. That’s all we know.

Checking the folders and files in Google Drive, there is no difference between the working folder and the problem folder.

I have cleared the cache.
The same issue occurs with all newly created shortcodes. Old ones seem ok.

Any ideas on how to resolve this problem.