We are a small business and have AT&T business DSL Internet service.  We have an Exchange server on site, but use an AT&T SMTP server as a smart host.  Some messages we send to hotmail.com addresses deliver fine, however some bounce back with this message:

The following recipient(s) could not be reached: 

  <user>@hotmail.com on 11/3/2009 8:29 AM
  The e-mail system was unable to deliver the message, but did not report a specific reason. Check the address and try again. If it still fails, contact your system administrator.
  < nlpi157.prodigy.net #5.0.0 SMTP; 550 SC-001 Mail rejected by Windows Live Hotmail for policy reasons. Reasons for rejection may be related to content with spam-like characteristics or IP/domain reputation problems. If you are not an email/network admin please contact your E-mail/Internet Service Provider for help. Email/network admins, please visit http://postmaster.live.com for email delivery information and support>

It appears that nlpi157.prodigy.net is the problem, because the messages to hotmail.com that succeed use a different server (nlpi129.prodigy.net).

We are not having this problem with any addresses other than hotmail.com addresses.  Please advise on what steps need to be taken to resolve this problem.  Thank you.

Here's more information from the bounce message that may be helpful:

Final-Recipient: RFC822; <user>@hotmail.com
Action: failed
Status: 5.0.0
Diagnostic-Code: SMTP; 550 SC-001 Mail rejected by Windows Live Hotmail for policy reasons. Reasons for rejection may be related to content with spam-like characteristics or IP/domain reputation problems. If you are not an email/network admin please contact your E-mail/Internet Service Provider for help. Email/network admins, please visit http://postmaster.live.com for email delivery information and support
Last-Attempt-Date: Tue, 3 Nov 2009 07:29:56 -0600

Hi crum66, thanks for reporting this.

Please post the domain or e-mail address that you’re using to send to your Hotmail contacts.

You can ask the admin of your domain to visit http://postmaster.live.com and review our policies and guidelines. If you also know the contact e-mail of your domain admin, please post it here so that our team can directly contact them.

The domain that we are sending from is hostetter-ohara.com.  However, if you look at the original error message, hotmail is complaining about prodigy.net. 

I am the domain admin for hostetter-ohara.com, so you can contact me for any technical details.

Thank you.

crum66, thank you for the information. I’ve forwarded your concern to the Windows Live Hotmail Sender Support Team. This team is dedicated to resolving message delivery issues as quickly as possible.

BTW, you mentioned that you are the domain administrator of hostetter-ohara.com, you can post an e-mail address here where you’d like to be contacted by the Windows Live Hotmail Sender Support Team. I'll relay your contact information to their team.  

Thank you for your prompt response.  Please have the support team contact me at {removed email address}.