Can't send mail to HOTMAIL

Just today a user told me that e-mail being sent to a HOTMAIL account was not going through. We’ve been using Domino mail for a long time and nothing has changed recently in our environment. I searched this forum and did not find anything similar.

In looking through the logs I see some e-mails to HOTMAIL are being delivered but after a number of failed attempts. This is the error I am seeing in the server log:

Failed to connect to SMTP host HOTMAIL.COM because 221 Closing connection. Good bye

Does anyone have any idea about what is going on here or how to resolve it?

Thank you!

Subject: Can’t send mail to HOTMAIL

A 221 should only come in response to your server issuing a QUIT command (QUIT + CRLF). It’s the receiving server’s way of saying “Okay, bye”. Perhaps Hotmail was too busy distributing spam to follow up on the handshake?

Subject: Can’t send mail to HOTMAIL

Generally that’s because of how the hotmail servers see you when you connect. make sure you have reverse dns for the server that is making the connection to hotmail. A lot of web-based email joints are like this.

Hope that helps.

Subject: RE: Can’t send mail to HOTMAIL

Our company has began experiencing this about 3 weeks ago on a 6.5.4 server. We can’t get any messages to go through to MSN or Hotmail. I’ve even got my own account over there which allows all e-mail to arrive. We’ve got rDNS setup correctly and are on a T1 provided by XO. Just wondering if there was anything specific to Domino SMTP that keeps MSN/Hotmail from accepting e-mail?