I appreciate whatever help you can provide. Here's the problem: I publish a WordPress blog to which a friend with a Comcast email address tried to subscribe. He signed up and was told he would receive a confirming email, which never arrived. He has tried many times, with the same result. I forward him emails I receive from WordPress when I have made a new post. He never receives them. I would go to my blog using Safari and send him my post via email. He wouldn't receive it. I then send myself an email using my Comcast address. I would not receive it. I would then send it to my gmail account, and I would receive it (a test I repeated a few minutes ago, with the same result). Both of us have checked our Comcast email spam filters, and found nothing that would cause this problem.