I am unable to send an email to my work address. @usace.army.mil
I keep getting a reply that says "This is an automatically generated Delivery Status Notification. Delivery to the following recipients was aborted after xxx hour(s):" "Reason: Temporary Failure"
As a test, try sending to that domain using some other, non-Comcast, address you have like Yahoo or Gmail or something. Does the same thing happen?
Then you need to call Comcast security and see if there is a blocking issue for that domain------------
Comcast Customer Security Assurance-------------------
Normal business hours (6:00 am to 2:00 am EST, 7 days a week)
1 - 888-565-4329