Why does Set Up Mail Client recommend the server hostname?
The Set Up Mail Client interface in cPanel recommends the server's hostname when an email account's domain does not have a valid SSL certificate installed. If the email account's domain has a valid SSL installed, the interface will recommend the email account's domain.
The Set Up Mail Client interface will also recommend the server's hostname instead of the email account's domain if the permissions of /var/cpanel/ssl/domain_tls/$DOMAIN/ are less than the default permissions of 0755 (replace $DOMAIN with the email account's domain). If the permissions of /var/cpanel/ssl/domain_tls/$DOMAIN/ are not 0755, please see the following article for information on how to change file or directory permissions: How do I change permissions on a file or folder?
Please see our documentation for more information on the Set Up Mail Client Interface: