Hotmail Senders receiving NDR : "550-Please turn on SMTP Authentication in your mail client..."

Question

Recently, senders from Hotmail have begun to get the following NDR when trying to e-mail our domain.

EDIT : Full NDR Message

Action: failed Status: 5.5.0 Diagnostic-Code: smtp;550-Please turn on SMTP Authentication in your mail client, or login to the 550-IMAP/POP3 server before sending your message. 550-snt0-omc3-s36.snt0.hotmail.com [65.55.90.175]:49271 is not permitted to 550 relay through this server without authentication

This is seemingly out of the blue and I'm at a loss as to why this is happening.

Pertinent Information

• We have multiple domains hooked up to our Exchange server. We changed our company name in January of this year, and the old primary domain (olddomain.com) will accept e-mails from Hotmail accounts, however e-mails sent to the new primary domain (newdomain.com) bounce back with the NDR listed above.
• The bounces only appear to be happening when the Hotmail sender is sending a new e-mail, and not if they are responding to an e-mail sent from our end.
• We have made no changes to the configuration of our server recently. This e-mail first appeared last Friday.
• As far as I can tell, the mail doesn't even seem to get to our server
• We performed an Exchange 2003 to 2010 migration last year. The 2003 acts as a Smart Host

Any advice on this issue would be greatly appreciated! I'm at a loss

Solution

Is your Exchange Server configured to be autoritative for this Domain?

Hub Transport -> Accepted Domains

Comments

[Greg Askew]

When you send an email message from your hotmail account, in the bounced message, what is the ip address and name of the SMTP server that is rejecting your message?

[DKNUCKLES]

Edited question with full NDR method.

[MichelZ]

Is it absolutely only hotmail which fails? All others are coming in fine? Really strange...

[DKNUCKLES]

Hotmail is the only domain I've identified / has been brought to my attention. All other external e-mail works as it should

[MichelZ]

Just to be sure, can you try testexchangeconnectivity.com If that really works, I think you have to open a case with Microsoft/Hotmail to further troubleshoot

[DKNUCKLES]

Green lights all around for the inbound SMTP test. I guess Microsoft is my next stop - thank you for your help MichelZ

[Admin]

Same situation here, except not using exchange. I am using google accounts for my domain. Any email sent from hotmail/live/msn gets the same ndr. This just started happening and doesn't happen when a client sends from any other mail service

[DKNUCKLES]

Based on my research it looks as though Google Apps and Exchange servers are the only ones affected by this little 'ism.

[Admin]

I also have the same situation. We can send emails to Hotmail, but Hotmail users can not send email to our exchange server. MX, rDNS, SPF are all OK - no issues with any other domains!

[Admin]

We have the same problem, started Friday 6/15. Hotmail bounces and gives the same diagnostic code to our google apps mail addresses.

[DKNUCKLES]

No it is not. The only authoritative domains are the ones that we own.

[MichelZ]

This is what I mean. your olddomain.com and your newdomain.com are listed here?

[DKNUCKLES]

Yes both domains are listed there. I apologize for confusion. The odd part here is that olddomain.com is listed as the default, but e-mails are leaving the organization as newdomain.com

[MichelZ]

The Settings on the individual user decides on what Domain to send as. (the bold SMTP address).

[DKNUCKLES]

Thank you for your insight on this! I've launched a ticket with Microsoft but have yet to hear back. If /when I do I'll post back.

[broadway1978]

As of this morning this problem appears to be resolved. Never got any more insight from MS - but it's working which is the main thing.