I just sent an email to three people. I got a "Delivery Status Notification" reply seeming to indicate that there was some problem delivering the message to at least one of the addressees.
The message body on includes one cryptic line:
[Return Code 550] sid: ueoa1p0083zXDDo01 :: 5.7.1 more information. k4si1155354icv.100 - gsmtp
Then there is an attachment, filename="ATT00015.eml", which appears to be the body of the original email but with the HTML exposed.
Is there any way I can tell which of the three addressees didn't get the message?