Symptoms

"Failed to get Session by Unexpected error" occasionally occurs if you operate in the following steps.

1. Open Jira issue detail screen.
2. Open another tab of the browser before the Alfresco panel is completely loaded.
3. Go back to tab of Jira issue detail screen.
4. "Failed to get Session by Unexpected error" occures.

Causes

Analytics Client Plugin put an HTTP header called x-atlassian-mau-ignore. This header causes Alfresco's CORS to be restricted and an error.

Access-Control-Request-Headers:authorization,x-atlassian-mau-ignore

Workarounds

There are one possosible workarounds.

1. Put x-atlassian-mau-ignore to cors.supportedHeaders in Alfresco's CORS setting.
   1. Open and Edit /opt/alfresco-content-services/tomcat/webapps/alfresco/WEB-INF/web.xml
   2. Find cors.supportedHeaders and put x-atlassian-mau-ignore.
      
      
   3. Restart Alfresco.

Reference

Atlassian Community : What is the 'x-atlassian-mau-ignore' header & why is my JIRA server rejecting it?