So here is our problem, an invoice-style HTML message is being sent from an Amazon AWS IP and the SMTP configuration is correct, the relay is allowed for this user. The delivery of the message is not the problem.
The problem is that when the messages are delivered to external email addresses, they have no content, only an attachment ( the attachment is actually a .jpg file, which has it's own issue - the extension is missing ). When the messages are sent to a smartermail local user, and the message is no longer sent externally, the HTML content is displayed fine.
We've taken one of the locally delivery smartermail messages to my personal email and we DO SEE the HTML content but not when the SMTP service sends the message from the web platform.
This is strange...anyone have some ideas for where I should check?