In your Box Admin Console, navigate to Users → Managed Users and find the OAuth user account being used for the Glean integration
Verify that the user’s role is set to “Admin” (not “Co-admin”)
If the user is currently a Co-admin, upgrade them to full Admin status or configure Glean to use a different Box account that has full Admin privileges
Note: Only one user can have the Admin role, so you may need to transfer admin rights from the current Admin
Alternative: Consider using JWT (Server Authentication) instead of OAuth 2.0, which doesn’t have this admin role requirement