I can't send emails today from my Comcast address to yale.edu

Starting this afternoon, I can't send emails from my Comcast address to any yale.edu addresses, though I can receive them. This is a huge problem, since I am a Yale professor. I get a bounceback with "Message could not be sent to the following recipients:[Name]  Domain unrouteable, possible DNS misconfiguration."

Could this have anything to do with today's Microsoft problem? Or is it something else?

Xfinity: Please notice this post and help me!