When outputting from a custom button, the error message "Insufficient Privileges / You do not have the level of access necessary to perform the operation you requested." is displayed.
Grant access to the Visualforce Pages. If you have created a Visualforce page for batch output from the list view, please grant access permission to the created Visualforce page.
When a guest user outputs a file in Experience Cloud, the error message shows, "You don't have access to the template file. Access to the template file requires permission to read the OFC_Template record.".
For guest users, the organization's share settings are set to private for all objects. Access permissions to the OFC_Template object for guest users require the sharing rule. See the Salesforce help below for more information.
Best Practices and Considerations When Configuring the Guest User Profile
Create Guest User Sharing Rules
Test Guest User Access in Your Experience Cloud Site