Multiple @comcast.net emailers receive mailer-daemon because their email is not delivered to one specific address

Basically, people with @Comcast.net can receive emails from the @sobelnet.org domain, but if a comcast.net emailer tries to send an email to the @sobelnet.org domain, it never gets delivered, and the sender receives a mailer-daemon hours or days later.  It's not just a problem with one individuals email account, it's multiple independent individuals with comcast.net that can't send an email to the @sobelnet.org address

No, my question was not answered.

Oh, and my domain and email service is DOTEASY.COM.

@Sobelcat When it customer to issues of blocked domains or issues sending or receiving emails from certain services you will typically need to work with our Customer Security Assurance team to see why this domain is having issues. You can either file a report at https://spa.xfinity.com/report or call them directly at

1-888-565-4329, and they can get a ticket opened. If you are having issues with both options then let us know, and we can reach out to our contact in that department. 

I already have a ticket number with them, the back office Tier II people

[Edited: "Personal Information"]

and they haven't called me in days....