Unable to delete addon domain: The domain userdata file appears to be missing

Symptoms

When trying to delete an addon domain, the following error is presented:

CONFIG_TEXT: Error: The domain userdata file for the domain.tld appears to be missing.

cPanel stores information about domains in the file: /var/cpanel/userdata/$username/$domain.tld

Note: "$username" is the cPanel username and "$domain.tld" is the domain or corresponding subdomain (if it's an addon domain) name.

This userdata file is missing or corrupted, resulting in the above error when removing domains.

The missing/corrupt userdata file(s) need to be restored from a backup, or the domain's cruft entries must be manually removed from the server.