Some mail servers allow for ‘Undisclosed Recipients’ to be used as the ‘To:’ address when sending Bcc mails for privacy reasons.
JEMHC will not be able to process these emails, unless you use the ‘Missing To: Address’ pre-processing task:
Enabling the ‘Missing To: Address’ Pre-processing Task
In your JEMHC Profile, click the Edit icon and scroll down to find ‘Pre Processing Tasks’
Enable ‘Use PreProcessed Message’ and then select ‘Missing Recipient Address Fixer’ from the list of tasks.
In here add the default To: address that you want to be used whenever a mail with an incorrect To: address is processed. Make sure it matches a catch email address so that the mail can be processed successfully