We have become aware that server NC027 has again been placed in the private block list of a major email provider. About three weeks ago Yahoo blocked this mail server for no good reason — and refused to reveal the nature and source of the alleged complaints that they received — and now Hotmail/Outlook.com has done the same. This means that all email to various Hotmail domains (including outlook.com) is being bounced immediately. Here is what the bounce message looks like for the hypothetical email address example@hotmail.com:
<example@hotmail.com>: host mx1.hotmail.com[207.46.8.167] said: 550 SC-001
(BAY004-MC5F27) Unfortunately, messages from 212.71.255.195 weren't sent.
Please contact your Internet service provider since part of their network
is on our block list. You can also refer your provider to
http://mail.live.com/mail/troubleshooting.aspx#errors. (in reply to MAIL
FROM command)
This mail server’s IP address is — as usual — NOT in the major block lists / blacklists, all of which can be checked using a website like MXToolBox. This service checks 105 known blacklists, and we are listed in exactly 0 (zero) of them.
I will echo the advice that we posted during the Yahoo problem: If you’re forwarding email from your domain to a Hotmail account, we strongly suggest that you stop doing that. If you’re doing that or using personal, free accounts for business use on Hotmail or other free email providers, we also strongly suggest you stop doing that. If you need help achieving — with your own domain and the hosting services you’re already paying for — what you’re currently doing with free email accounts with third-party providers, talk to us and we’ll help you do it a better way.
Additionally, if you’re running a mailing list by blind-copying (or, even worse, simply cc’ing!) any more than about a dozen email addresses (of close friends or family), we suspect that this may be the cause of the recent problems. Within the next 30 days we will be implementing limits on the number of email addresses that can be cc’d or bcc’d in a single message. If you’re doing this, please contact us for options to ensure that your mailing list can continue to operate.
We are attempting to resolve this issue with Microsoft and will post updates here. Thanks for your patience.
