Summary

Users are no longer able to edit a page or create a page while the collaborative mode is ON and Confluence has a Context path. The following error messages may appear in a pop-up error dialog:

Also, while checking the HAR file we could see 404 for /synchrony-proxy. 

Diagnosis

According to the "Possible Confluence and Synchrony Configurations," Confluence offers two methods for Synchrony configuration: "With Reverse Proxy" and "Without Reverse Proxy." In the case of the "With Reverse Proxy" configuration, users may face connectivity issues with /Synchrony if the reverse proxy setup lacks the necessary Synchrony settings (e.g., Nginx, Apache, Haproxy, etc.). In such instances, Confluence utilizes a fallback method, allowing users to connect to Synchrony through the Confluence internal proxy accessed via the "/Synchrony-proxy" path. This alternative approach should function effectively in all scenarios.

However, if Confluence incorporates a context path, the Synchrony external URL must account for the Confluence context path. Failure to reach the correct path will result in a "404 Page Not Found" error. To diagnose the problem and confirm successful Synchrony connection through Confluence, users should run the provided URL within the same browser session where they have already logged in, ensuring user authentication is preserved.

https://<Confluence-Base-URL-With-ContextPath>/synchrony-proxy/heartbeat

If the above URL returns a 404 error, it indicates a problem with the Confluence configuration or a missing context path. This issue is likely the cause of the 404 error for the Confluence Synchrony internal proxy.

Solution

If the following URL https://<Confluence-Base-URL-With-ContextPath>/synchrony-proxy/heartbeat is giving a 404 then we could check the following properties to make sure everything is configured properly and nothing is missing. 

• Check the /Synchrony-proxy context path in the server.xml file and make sure it is present.

  <Context path="${confluence.context.path}/synchrony-proxy" docBase="../synchrony-proxy"
                           reloadable="false" useHttpOnly="true">
                      <Valve className="org.apache.catalina.valves.StuckThreadDetectionValve" threshold="60"/>
                  </Context>

• The following JVM property should be present in the setenv.sh file. 

  CATALINA_OPTS="-Dconfluence.context.path=${CONFLUENCE_CONTEXT_PATH} ${CATALINA_OPTS}"

• Check the following property is correctly configured with the correct context path in the confluence.cfg.xml file. 

   <property name="confluence.webapp.context.path">

• Last check the following properties are present in the setenv.sh file

  CONFLUENCE_CONTEXT_PATH=`$JRE_HOME/bin/java -jar $CATALINA_HOME/bin/confluence-context-path-extractor.jar $CATALINA_HOME`
  export CONFLUENCE_CONTEXT_PATH