To Whitelist an email address means that you want to recieve email from this domain - even if it is marked as Spam.
To Blacklist an email address means that you do not want to recieve email from this domain or email address.
To Whitelist or Blacklist an email addresses in your Alpine Hosting Account, you must first login to your cPanel account:
Once you have logged in navigate to:
Email > MailScanner > Email Blacklist/Whitelist Settings
Folow the instructions to an Email Address to the Whitelist or Blacklist form fields.
If you have any additional questions please Submit a Support Ticket: