Issue Summary

The product administration and Confluence guest access allow us to set a group with both guest access and product access to Confluence, which results in some undefined errors that doesn't tell us what is wrong.

Steps to Reproduce

1. Create a group (let's call it Guests);
2. Grant this group with Guest Access;
3. Add this group to the Confluence product access as well;
4. Add a user to this group;
5. There are two actions that trigger undefined errors:
   • Scenario A:
     • Navigate to Confluence Administration > Global Permissions > Guest Access;
     • Click in the Guest group's ellipses > Manage guest access
   • Scenario B:
     • Navigate to the user's profile in the site;
     • Next to "Confluence Guest", click over Manage space access

Expected Results

We could expect a few different things:

• The Site Administration hub won't allow us to add a guest group to grant product access as well;
• Global Permissions on Confluence could state the reason why we are not able to manage Guest Access within the product (due to the fact the group(s) are also granting product access).

Actual Results

Scenario A: we are redirected to an error page under the Confluence administration hub to the enpoint /wiki/admin/permissions/global/group/8b03a14b-6872-4acf-8a51-9636d5a8d6d2

Scenario B: we are redirected to this endpoint /wiki/admin/permissions/global?tab=external&addSpaceAccess=true&users=62b36711566f3e7b0a900829 (which is the correct one that is expected on Scenario A), and it opens a pop-up modal window with a red error message stating: "Some users couldn't be added. Try searching for them, or refresh the page."

Workaround

Remove the Guests group you set from granting product access to Confluence.