Issue Description

When Service Desk is integrated with Confluence 6.15.4, the following issue happens: when a customer clicks on a KB article from the Service Desk Customer Portal, they get the following error:

The knowledge base article could not be found

Note that when the Customer clicks on the same KB article from the issue creation form, the page loads properly:

Steps to Reproduce

• Install any Service Desk version such as 3.15.x, 3.16.x, 4.1.0
• Install Confluence 6.15.4
• Create an application link between Confluence and Service Desk using Oauth with impersonation
• Configure an external user directory in Confluence using the JIRA directory to ensure that the JIRA users exist in Confluence
• Create a space in Confluence
• Create an article in this space (with "laptop" as a title)
• Create a new Service Desk project, and configure the Knowledge Base setting as follows:
  • Use the space created in Confluence
  • Select the option "All active users and customers can access the knowledge base without a Confluence license"
• Log into the Service Desk customer portal with a user which does not have a Confluence license
• Search for the KB article by typing "laptop" in the search box
• Click on the KB article

Observed

• The KB article loads forever (we get a spinning wheel)
• If we refresh the page, we get the following error in the UI:

  The knowledge base article could not be found
  

  

• If we collect a HAR file, we get a a 404 error with the request "/rest/servicedesk/1/customer/models"
• The following error is thrown in the logs:

  2019-06-06 14:48:54,958 http-nio-8080-exec-7 ERROR customer1 888x235x1 oqwnl5 0:0:0:0:0:0:0:1 /servicedesk/customer/kb/view/884742 [c.a.s.i.api.applink.BaseAppLinkResponseHandler] Applink request has returned an error %s
  2019-06-06 14:48:54,958 http-nio-8080-exec-7 ERROR customer1 888x235x1 oqwnl5 0:0:0:0:0:0:0:1 /servicedesk/customer/kb/view/884742 [c.a.s.i.api.applink.BaseAppLinkResponseHandler] Confluence could not find the requested page and returned a 404
  

Additional notes

• The issue occurs whether the Confluence application is configured with anonymous access or not
• The issue does not happen in the 2 following scenarios:
  • The user has a Confluence license: in this case, this user can open the KB article from both the Customer Portal homepage, and from the request creation form
  • The user does not have a Confluence license and opens the KB article from the request creation form