Problem

When adding watchers to a page using the "manage watchers" interface, the user picker box finds the appropriate user from the user list.  After selecting the user, a message popup immediately appears in the browser, with the following message:

This page at (baseurl) says: Failed to add watcher: error

The watcher is correctly added. However, the "Manage watchers" interface does not reflect this until the interface is closed and reopened.

A similar issue occurs when deleting watchers using the "Manage watchers" interface.  After clicking the trashcan icon, a popup appears in the browser with the following message:

This page at (baseurl) says: Failed to delete watcher. Refresh page to see latest status.

The watcher is correctly deleted, but the "Manage watchers" interface must be closed and reopened to reflect this.

Diagnosis

Bypass the proxy and connect to Confluence directly on the server. If the error does not occur, the resolution will correct the issue.

Cause

Failing to add the proxy attributes to the Connector element in the server.xml file when running Confluence behind Apache with mod_proxy:

proxyName="proxy.example.com" proxyPort="443" scheme="https"

Resolution

Revisit the following article: Using Apache with mod_proxy. Ensure that the two steps listed here have been completed.