I have posted on this issue before and wanted to add more, but apparently the thread is closed. I receive emails from one sender sent to a distribution list from her iPhone, and I am on that list. I once suspected the problem was a pdf attachment to the email but no longer believe that to be the case.This morning I received an email from the sender without an attachment and got the same result: "This message was not processed because it contains an invalid recipient." This first line is followed with a lot of header information. If there is a pdf attachment, it, too, is converted to header-type information, and the attachment is unreadable. I only experience this result when I read the email on my Windows 10 PC using Outlook 2013 with Norton 360 AntiSpam turned on. I do not get this gobbledygook if I read the email on my Android phone before reading it on my PC (although once opened on the PC it reverts to this mess on all devices). If I turn AntiSpam off in my PC Outlook 2013, the problem disappears. I have added this sender to the Allowed List in AntiSpam. It doesn't help. I would rather be using AntiSpam if possible.
I suspect the problem is how AntiSpam processes emails from an iPhone sent to a distribution list. The Apple distribution list format is:
DistributionListName <email @ xxxxx . com, email @ yyyyy . net, email @ zzzzzz . org>
I suspect it is the "DistributionListName" that is confounding Norton 360 AntiSpam and is interpreted as an invalid recipient. Is there a way to fix this? I really want to be able to read emails from this sender and, also, use AntiSpam.
Thanks, Bob
[Edit: Removed hyperlink to a potentially malicious page to conform with the Participation Guidelines and Terms of Service]