[Mailman-Users] Delivery error

[Miguel Marques]

  Hello

  I installed mailman 1.1 some months ago, and I've been having since then
some problems. I searched the FAQ and mailing-list archive, but haven't
found anything!!
It seems that the adresses *hotmail.com and *ip.pt (a
portuguese ISP) do not work, although all other adresses work without
problems. The error I get is:

554 <xxx at hotmail.com>... Service unavailable

Final-Recipient: RFC822; xxxo at hotmail.com
Action: failed
Status: 5.0.0
Remote-MTA: DNS; mc2.law5.hotmail.com
Diagnostic-Code: SMTP; 554 Transaction failed
Last-Attempt-Date: Tue, 14 Mar 2000 12:09:34 GMT

I am using a Linux box running RedHat 6.1, with SendMail 8.9.3

 can anyone help me?

  miguel marques