Hey @CraigContact_Smith - we also received your help scout ticket.
Of course, we would love to help you on this matter. However, this issue might be better with the Plesk support, as the mails are sent through the Plesk server.
I highly recommend, that you contact the Plesk support directly on this matter. Please use the support form to submit a new request: https://support.plesk.com/hc/en-us/requests/new
Especially, if this solution here does not help, let us know if there is another solution to your issue: