Page Tree macro won't load for portal only users in the customer portal KB viewer page + dialog

Summary

• Page Tree macro won't load for portal only users when accessing a KB article from JSD customer portal (KB viewer page + dialog)

Steps to Reproduce

1. Create a JSD project and Link to a Confluence space
2. On Confluence, configure the following page structure:
   Confluence page structure

   • Page 1
     • Page 1.1
       • Page 1.1.1
         • Page 1.1.1.1
         • Page 1.1.1.2
         • Page 1.1.1.3
         • Page 1.1.1.4
       • Page 1.2
         • Page 1.2.1
           • Page 1.2.1.1
           • Page 1.2.1.2
           • Page 1.2.1.3
           • Page 1.2.1.4
   • Page 2
   • How-to Articles

1. On page 2, configure a Page Tree Macro with Page 1 as Root Page
2. Open page 2 as a customer on customer portal

Expected Results

• Load page tree macro and show the full tree of Page 1.

Actual Results

• Page tree macro does not load;
• The below error is thrown in the browser console (tested Chrome and Firefox)

  Mixed Content: The page at 'https://gattino.atlassian.net/servicedesk/customer/kb/view/1736825?applicationId=255b83af-5e0d-3e1d-a9a4-428a9150f371&title=How+to+add+a+page+tree+macro%3F&spaceKey=CS&q=how+to+add&q_time=1518194091684&portalId=1' was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint 'http://gattino.atlassian.net/login?dest-url=/wiki%2Fplugins%2Fpagetree%2Fnaturalchildren.action%3Fdecorator%3Dnone%26excerpt%3Dfalse%26sort%3Dposition%26reverse%3Dfalse%26disableLinks%3Dfalse%26expandCurrent%3Dfalse%26hasRoot%3Dtrue%26pageId%3D1704024%26treeId%3D0%26startDepth%3D0%26mobile%3Dfalse%26ancestors%3D1605879%26treePageId%3D1736825'. This request has been blocked; the content must be served over HTTPS.
  

Workaround

• Edit the Confluence page and replace the Page Tree macro with a Children Display macro, setting the Parent Page to be the root page of the page tree you want to display.