Zones are not synced via DNS extensions in Plesk

Symptoms

• Synchronization of all DNS zones via any DNS extension fails.

• The following messages are found in /var/log/messages:

  CONFIG_TEXT: node2 named[1591]: zone example.com/IN: zone serial (2018070713) unchanged. zone may fail to transfer to slaves.
  node2 named[1591]: client 203.0.113.2#59417 (example.com): query (cache) 'example.com/MX/IN' denied
  node2 named[1591]: client 203.0.113.2#33475 (example.com): query (cache) 'example.com/MX/IN' denied

• The slave-dns.php value for DNS Connector can be found in Plesk database:

  # plesk db "select name, value from ServiceNodeConfiguration where value like '%slave-dns.php%';"
  +---------------+-----------------------------------------------------------------------+
  | name | value |
  +---------------+-----------------------------------------------------------------------+
  | custom_script | "/usr/local/psa/bin/extension" --exec slave-dns-manager slave-dns.php |
  +---------------+-----------------------------------------------------------------------+
  1 row in set (0.00 sec)

• (For Amazon Route 53) The following is found in /var/log/plesk/panel.log when Debug mode is enabled:

  CONFIG_TEXT: DEBUG [util_exec] [5b40802f9e487] Starting: dnsmng --update example.com, stdin:
  DEBUG [util_exec] [5b40802f9e487] Finished in 0.27194s, Error code: TRUE, stdout: , stderr:
  INFO [panel] All zones registered in Plesk were synchronized with Amazon.

Cause

Slave DNS Manager is being used instead of a DNS extension as a third-party DNS service backend.

Resolution

Reinstall the external DNS extension:

Warning: After applying the below steps, Slave DNS Manager extension will not function.

1. Log in to Plesk.
2. Remove the installed DNS extension under Extensions > My Extensions:
3. Install it again under Extensions > Extensions Catalog.

In order to switch back to Slave DNS Manager without uninstalling the external DNS extension, connect to the server via SSH and execute the following command:

# plesk db "update ServiceNodeConfiguration set value='"/usr/local/psa/bin/extension" --exec slave-dns-manager slave-dns.php' where name='custom_script';"