E-Mail accepted by smtp.comcast.net, but never delivered

I'm having an issue that started sometime late yesterday (12/31/2019).

I am sending outgoing e-mails to smtp.comcast.net, using TLS on port 587.  I get a response in my logs that the message was accepted for delivery.  However, the messages are never delivered, neither to an inbox or a spam folder.  I've tried sending mail to several different outside addresses and none are being delivered, so I've narrowed this issue down to a problem at smtp.comcast.net.

Anyone else having this issue?  My outgoing e-mail setup has been working fine for ages and I haven't changed anything.

Thanks