When linking Confluence with Service Desk and allowing Any Active User to see the space, it will provide access for customers that do not have a license in Confluence.

By allowing access to the pages, if using a Jira macro (or any macro to retrieve Jira content), if the same is restricted to other users, not including the customers in question (e.g. everyone/non-logged users), the macro will display a message that the JIRA project doesn't exist or you don't have permission to view it..

This is a suggestion to allow customers from open spaces to access the Jira issues tickets in Confluence side, independent of the restrictions from Jira.

Note: This also applies to a Service Desk customer who has a license in Confluence.