If you want to allow all emails to be received from a specific sending email address – so that even mails classed as ‘junk’ will arrive – then you can ‘whitelist’ this address within Junk Mail Filters within the package.
Login to StackCP.
Select the package where your mailboxes are located
Locate ‘Allow by Sender’ and add a domain rule or a mailbox rule to allow mail to always be received from a specific address