Troubleshooting Collaborative Editing

Collaborative editing is powered by Synchrony which synchronises data in real time. Under normal circumstances it should not need to be managed manually by an administrator.

This page will help you troubleshoot problems with Synchrony in your instance. 

First steps

Check Synchrony is running

To check if Synchrony is running, go to   > General Configuration  >  Collaborative editing

Note: if you're running Confluence Data Center, this page will only be able to tell you if the current Confluence node is connected to your Synchrony cluster. You may want to use a third party monitoring tool to help you monitor your Synchrony cluster.  

Check you can edit a page

If you see an error when you edit a page, but Synchrony is running, something is preventing your browser from connecting to Synchrony. 

The most common issue is a misconfigured reverse proxy. See our proxy troubleshooting tips later in this page or head to Administering Collaborative Editing to find out more about possible proxy and SSL configurations.  

On this page:

Related pages:

Check the logs

You can find the Confluence application logs at <home-directory>/logs/atlassian-confluence.log and Synchrony specific logs at   <home-directory>/logs/atlassian-synchrony.log.

Restart Synchrony

Go to  > General Configuration > Collaborative editing and choose Restart Synchrony.  

Check port 8091 is available

Synchrony runs on port 8091 by default. If this port is already in use by another application on your server you can use the the synchrony.port system property to change it to an available port.  

(If you're using Confluence 6.0.3 or earlier you'll need to use reza.port instead of synchrony.port.)

See Configuring System Properties to find out how to change this. 

For Confluence Data Center the way you run Synchrony is a little different. See Configuring Synchrony for Data Center for more information.

Reverse proxy issues

If you have configured your reverse proxy, but can't edit pages, here's some things to check in your configuration:

  • Go to installation-directory>/conf/server.xml and check the Connector directive. Make sure that you have correct values for <protocol> and <proxyName>. See the examples in the guides below for more information.  
  • The http connector always needs to be present in the <installation-directory>/conf/server.xml file, even if you're configuring SSL or using the AJP connector. The Synchrony health check uses HTTP and will fail if this connector is not present. Alternatively, if you do not want to include the http connector, you can use the synchrony.proxy.healthcheck.disabled system property to disable the health check. 
  • If you're using Apache, make sure you're using Apache 2.4 (with WebSockets support) and all required modules have been enabled (mod-proxymod_rewriteproxy_wstunnel).
  • If you're using Apache and want to connect directly to Synchrony, in your proxy config file, make sure you've included /synchrony and that the order of the Confluence and Synchrony directives and location blocks is correct. See the examples in the guides below for more information. 

See Administering Collaborative Editing to find out more about possible proxy and SSL configurations then check out the following guides for more information on how to include Synchrony in your reverse proxy config, if you want to connect direct to Synchrony:

Forward proxy issues

If you're using a forward or outbound proxy, you will need to add the IP that Synchrony listens on to your config to ensure it is bypassed. See Configuring Web Proxy Support for Confluence for more info.

By default, the IP is 127.0.0.1, or it will be the value of the synchrony.host system property, if you've customised the hostname or IP that Confluence uses to connect to Synchrony. 

Websocket issues

Collaborative editing works best with a WebSocket connection. If one can't be established due to a timeout, or a proxy server or firewall that doesn't allow WebSocket connections, the editor will attempt to connect via an XML HTTP Request (XHR).

You can use http://websocket.org/echo.html to perform a quick HTML5 WebSocket test against an echo server.

SSL issues

Synchrony cannot accept direct HTTPS connections, so you will need to terminate SSL at your reverse proxy or load balancer, or at Tomcat if you are not using a reverse proxy.

Memory issues

If you experience out of memory errors related to Synchrony, you can change the heap size allocated to Synchrony using the synchrony.memory.max system property.

If you're Confluence 6.0.3 or earlier you'll need to use reza.memory.max instead of synchrony.memory.max.

See Configuring System Properties to find out how to change this.  

For Confluence Data Center the way you run Synchrony is a little different. See Configuring Synchrony for Data Center for more information.

Multiple Synchrony processes

If you see an error immediatley in the editor, but Confluence reports that Synchrony is running, check to make sure that you only have one Synchrony process running. 

If you do have multiple Synchrony processes running, stop Confluence, kill the additional Synchrony processes and then restart Confluence.

You can avoid this problem by always using stop-confluence.sh / stop-confluence.bat to stop Confluence, rather than simply closing the Tomcat window. 

Incompatible browser extensions 

Some third party browser extensions that interact with the editor, such as Grammarly, may not function correctly with collaborative editing. See Confluence Collaborative Editing blocks Grammarly Extension to find out how to disable Grammarly for just your Confluence site.

Firewall or anti-virus interference

We've had a few reports of firewalls or anti-virus software blocking some requests to the server, resulting in unexpected behaviour in the editor. You may need to add Confluence to your whitelist / trusted URLs if you experience issues. See Weird Page or Editor Behaviors with Kaspersky Internet Security for more information.

Too many people in the editor

We don't enforce a maximum number of people who can edit together, but we recommend you keep it to no more than 12 people editing the same page at the same time. We may enforce a limit to the number people who can enter the editor in a later release if necessary.

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