AutoSSL failing with the error: system failed to connect a UNIX domain socket to “/var/cpanel/dnsadmin/sock”

Symptoms

If you are encountering the following error after performing an AutoSSL check, this article can help you to further diagnose the issue:

WARN get_zones_for_domains(): Cpanel::Exception::IO::SocketConnectError/(XID pm24df) 
The system failed to connect a UNIX domain socket to 
“/var/cpanel/dnsadmin/sock” because of an error: Connection refused 
at /usr/local/cpanel/Cpanel/SSL/CAA.pm line 121. 

Description 

Based on this error, it indicates that the "dnsadmin" service cannot be reached properly. "dnsadmin" is a built-in cPanel service whose purpose is to increase performance of DNS record updates. Based on this error, the service is most likely down or needs to be restarted.

Workaround

Attempt to restart the "dnsadmin" service by running the following command:

/scripts/restartsrv_dnsadmin

If the service is not starting properly, you can check the dnsadmin log for any further errors that might be taking place. The log file for this service is located at: /usr/local/cpanel/logs/dnsadmin_log