We have Identified a problem with the bulk mailer on our cubecart version 4.4.4. All of our emails are falling into spam at the moment and the main issue is caused by an invalid message ID in the email headers.
For example, currently our message ID is sent as <randomletters&numbers>.<morerandomletters&numbers>@
I believe for this to be valid, the domain name after the @ should be present. As this is not the case at the moment our emails are being flagged as spam by numerous mail clients. How can I configure the bulk mailer to add the domain name after the @ in the message ID?