As far as I know, changing your email address in WHM has nothing to do with the email address linked to your domain name. Changing the email in WHM is just that: assigning a different email address for your web hosting account. to change the email associated with your domain name, you need to log in to your domain host (where your domain name is hosted) and change the email address there. Often your domain name is not hosted with the same company as your web hosting. Either way, it’s probably a different login.