Comcast blocking Hidden-tech emails without rhyme or reason,
you need to complain to Comcast customer service

  If you are using a Comcast email account, you need to complain to
Comcast that they are improperly blocking emails that are important to you.

The story is that once or twice a week all emails sent to Comcast users
start getting bounced with a message that looks like this:

Connected to but sender was rejected.
Remote host said: 550- blocked by
550 Blocked for abuse. Please send blacklist removal requests to
Be sure to include your mail server IP ADDRESS.

We have had to check daily for this problem and it takes Comcast another
day to clear it.

Comcast has provided no explanation of the basis for such action and
provided no method for being identified as a proper sender to their users.
We deal with many lists much larger than the HT list, on a wide variety of systems
and have had nothing like this lack of responsiveness from other services, including AOL.

This is extremely poor business practice and we suggest you both complain to your
Comcast customer service rep and stop using Comcast for your email.