Our email from campaigns gets flagged by spam engines with this error below. I looked at our own mailings and that of another Hubspot mailer and get the same result. I can change the received Hubspot email to plain text and clearly there is a subject and plain text, not just HTML. This flag carries a hefty penalty and we would like to satisfy the criteria for it to remove the penalty. Any ideas?
EMPTY_MESSAGE Message appears to have no textual parts and no
Subject: text
