Comcast IP blacklisted by 1and1.com

Hello quetek and welcome,

It usually not the actual smtp server that is blacklisted, it is your email account specifically. You need to contact 1&1's email blacklist folks to have your email address taken of of their blacklist. Somtimes if you send too many emails to a very large distribution list the email server perceive that to be a spammer.  Most blacklist folks will simply reinstate your email address.

Hope this helps you out.

I think it's confirmed that Comcast IPs are blacklisted.  There is already a thread about this problem.  I didn't see it when I posted my question.  Trying to delete my message but couldn't figure out how. 

Sorry, the thread seems to be an old one and the problem has been resolved. 

Anyway, MXToolBox shows that the IP is currently blacklisted by BACKSCATTERER.

Futhermore, according to the link in the bounce message:

554 No SMTP service - IP address is black listed

In order to reduce the number of spam e-mails received in our system, we use common RBL-lists to reduce the receipt of e-mail spam. These lists include dynamic IP addresses and IPs contain IP addresses which are dynamic on the one hand side and associated with sending known to send spam messages on the other hand. Please check if your IP address is on one of the above mentioned these lists.

Hello quetek,

Thank you for the follow-up post and glad to hear your issue has been resolved.