Unable to reconfigure domain on Plesk for Linux server: "proxy_cache" zone is unknown in /etc/nginx/nginx.conf:41

Symptoms

• Unable to suspend or recondigure domain example.com in Plesk:

  PLESK_ERROR: nginx: [emerg] "proxy_cache" zone "example.com_proxy" is unknown in /etc/nginx/nginx.conf:41
  nginx: configuration file /etc/nginx/nginx.conf test failed

• The option Proxy mode is disabled in Domains > example.com > Apache & nginx Settings.

• The option Enable nginx caching is enabled in Domains > example.com > Apache & nginx Settings.

• Password protection is configured in Domains > example.com > Password-Protected Directories.

Cause

This is the Plesk bug PPPM-11126, which is planned to be fixed in future product updates.

Resolution

Until the bug is fixed, use the workaround:

1. Connect to the server using SSH.

2. Back up the file /usr/local/psa/admin/conf/templates/default/domain/nginxDomainVirtualHost.php :

   # cp -a /usr/local/psa/admin/conf/templates/default/domain/nginxDomainVirtualHost.php{,.bak}

3. Download the patched file:

   # wget https://support.plesk.com/hc/en-us/article_attachments/360010816199/nginxDomainVirtualHost.php

4. Replace the original file with the patched one:

   # mv nginxDomainVirtualHost.php /usr/local/psa/admin/conf/templates/default/domain/nginxDomainVirtualHost.php

   Warning: If the custom configuration templates are used, the corresponding custom nginxDomainVirtualHost.php file should be recreated and reviewed.

5. Reconfigure the domain:

   # plesk repair web example.com