Summary

Users are unable to delete pages in Confluence. When attempting to do it, they are presented with the following pop-up message:

Environment

Confluence Server or Data Center

Diagnosis

Capturing a HAR file while trying to delete a page, we can see that the POST request returns an HTTP 200, everything seems to be working as expected:

200 POST https://confluence.domain.com/rest/page-hierarchy/delete    

However, crossing the timestamp of the HAR file with the information in the application logs, we can see the following error:

2021-07-30 15:21:04,868 ERROR [Long running task: Delete page hierarchy long running task] [dao.bulk.delete.DefaultBulkPageDelete] deepDeleteInternal Failed to acquire lock for delete page hierarchy: [com.atlassian.confluence.cluster.hazelcast.JvmDualLock@5d28f9f1]
 -- url: /rest/page-hierarchy/delete | referer: https://confluence.domain.com/pages/viewinfo.action?pageId=450581647 | traceId: 63b896bb0a835843 | userName: admin

Cause

The root cause for this problem is yet unknown, but it is possibly related to corruption in the plugin cache, at the OS level. 

Solution

Clearing Confluence's plugin cache is known to resolve the problem:

1. Shutdown Confluence
2. Ensure the user running Confluence has full read/write privileges to the confluence-home directory.
3. Remove the following directories (we recommend creating a temporary backup, in case some of the plugins stores metadata in these directories):
   
   • <confluence-home>/bundled-plugins
   • <confluence-home>/plugins-cache
   • <confluence-home>/plugins-osgi-cache
   • <confluence-home>/plugins-temp
   • <confluence-home>/bundled-plugins_language
4. Start Confluence
5. Re-attempt to delete the page