550 Mail rejected by Windows Live Hotmail for policy reasons

I have setup an online service which allows record labels to login, upload their music and then email their music to a list of djs which i guess works on the same principle that a newsletter would do.

The Record Labels are able to enter in their email address so when they hit send to the Djs the mail looks like it has actually came from their domain!

Recently, hotmail has started bouncing these emails back with the following error -

SMTP error from remote server after MAIL command:
host mx2.hotmail.com[]:
550 SC-002 Mail rejected by Windows Live Hotmail for policy reasons.
The mail server IP connecting to Windows Live Hotmail has exhibited namespace mining behavior. 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

Do you have any ideas on how i could get around this issue?
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hbustanConnect With a Mentor Commented:
Antispam solutions check for authenticity of email messages which means whatever you place in the reply-to will not matter. The idea is to stop people from sending mass e-mails from domains they do not own. Although you own your domain, your IP address is shared which means anyone with 1and1 can send e-mails from your domain as well and it will be difficult to pinpoint the blame.

If you have a dedicated IP address then no one but yourself will be blamed if spam comes from your domain when antispam devices validate your requests.
What email server do you have? Could you paste the NDR on this page.
I believe you need to make sure that the email address that is being sent matches your real domain name that has been registered for you.

Also Reverse DNS should work for these addresses and the corresponding MX records.

You can use "nslookup -q=mx yourdomainname" to see what IPs are set for your MX records and do another nslookup against these IPs to see whether they match the same domain name.
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Sailo100Author Commented:
Sorry i didn't see the other reply to this.....

Just thinking, perhaps i stuck this in the wrong section also.....

My apache server is just sending emails via smtp using 1and1's mail servers.  Is the problem that the domain name i am sending from is not registered at 1and1?  

If so, is there any way around this?  I mean if you pay a company to send out a larger mailer for you how do they get around it when the email arrives saying its from another domain?
That is most likely the reason.

Most Anti-Spam solution these days try to identify the sender and match their IPs to their domains and their domains to their IPs before validating.

Since your domain name might match the IP, the reverse is not true in your case as the IP will most likely map to 1and1 domain name instead of yours.

The only way around this is to have a dedicated IP address and register the DNS and Reverse DNS for your mail server to be valid.
Sailo100Author Commented:
Ok i understand...... does this apply to the from address only?

Meaning if i have the fron address as my domain address and the reply to address as another?

Paypal for example send emails saying From something@paypal.com on Behalf of Somebody Else and when you hit reply it goes to another address?

Is this an option to deploy?

Sailo100Author Commented:
Thanks for all of your help!
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