Problem

Application links from Confluence to Jira are not working as expected. The application link in Confluence which connects to Jira shows Network Error for the status. 

The following message appears in a Jira macro on a Confluence page:

com.atlassian.sal.api.net.ResponseException: org.apache.http.conn.ConnectTimeoutException: Connect to jira.example.com:443 [jira.example.com/10.10.24.3] failed: Read timed out.

Diagnosis

Environment

• Confluence Data Center
• Jira Data Center
• Apache HTTPD reverse proxy 

Diagnostic Steps

1. Capture a HAR file or view the Developer Tools - Network tab while loading the Application Links page (under General Configuration)
2. Wait for the Application Links page to load and look for the Network Error status on the Jira application link 
   1. The status typically appears after ~10.5 seconds in this scenario
3. Look at the Network tab in Developer Tools and find the application link request to JIRA

4. Confirm it shows the following error: 

   error: {category: "UNKNOWN", details: "java.net.SocketTimeoutException: Read timed out", type: "UNKNOWN"}

5. Example: 
   1. 

Cause

The Apache HTTPD reverse proxy hosting Jira Data Center is missing a critical item in it's configuration file:

ProxyPassReverse / http://jira.example.com/

• The above example assumes the base-url for Jira is: https://jira.example.com

Resolution

1. Add the following line into the Apache httpd.conf file (or virtual server, depending on environment): 

   ProxyPassReverse / http://jira.example.com/

   
   

   1. The above example assumes the base-url for Jira is: https://jira.example.com

2. Restart Apache 

   sudo service httpd restart

3. Refresh the Applications Links page in Confluence