You may be correct about the Comcast 'technician's' assumption about Outlook and Outlook.com, but I did give them my e-mail address (xxx@comcast.net) during the tech assistance sessions. I think you are right about the Comcast address is being treated as spam by the Comcast server (however little sense that makes).

However, your analysis doesn't explain the entirety of my problem. Why does the issue persist when I send e-mail out on my laptop, an entirely different computer, using a different installation of Outlook, and even a different version (2019), while using a profile with my desktop e-mail address? Further, and I didn't mention this in my original post, but I also have the problem when sending e-mail from my iPad or iPhone, which I have set up to access the same comcast.net email account I use on my desktop? (In case you are wondering, I use a POP3 configuration, not IMAP.) It also makes no difference whether I am on my home network or using an xfinity hotspot. I can also change profiles on my desktop computer to a different comcast.net address and NOT have the problem.

In short: 1. No matter what computer or e-mail client I use, my xxx@comcast.net (desktop address) fails. 2. No matter what computer or e-mail client I use, ANY OTHER e-mail address works.

I have to conclude this is Comcast's fault, but they flatly refuse to do anything about it.


I also misspoke in my original post: I said I did NOT have the issue when using my desktop e-mail address in a profile on my laptop. I DO have the problem in that circumstance.