Exchange server queing

[imapc]

Hi all!
I am sending an email to a company and when I send it it is getting hung in the que and when I click on it the message is, "The remote server did not respond to a connection attempt."

I have researched this and believe it to be related to DNS, however all of my lookups resolve my address and name fine. Also the NDR numbers on the return message is #4.4.7 see below;

Your message did not reach some or all of the intended recipients.

Subject: testing
Sent: 3/6/2009 9:45 AM

The following recipient(s) could not be reached:

test@xxxxusa.com on 3/8/2009 10:53 AM
Could not deliver the message in the time limit specified. Please retry or contact your administrator.
<mail.server.com #4.4.7>

This link gives a list of the ndr codes and meanings and it states #4.4.7 lies with the receiving servers connector.

http://www.computerperformance.co.u...03_NDR.htm#Interpreting the Exchange 2003 NDR

they are able to receive email from everyone but us, we have no problems with other people just them. We are not on a blacklist, I have done my dnsstuff.com also this is a good site too,

http://www.mxtoolbox.com/index.aspx.

I went to this site and did a diagnostics and blacklist check on my server and everything returned was good.

Unfortunately the other company of course is not cooperating and assumes that because they are getting other emails that the problem lies on my side.

Any help is greatly appreciated

 

[imapc]

here is a little more where information that I just got to add to the other things I tried above.

I just got off the phone with the company hosting the mail server and they were able to telnet to my server from theirs,HOWEVER; he logged onto the server hosting the client's mail server that is not receiving the mail and was NOT able to connect and vice versa, I could connect to another server on the hosting network but not to the server hosting the mail for the company not receiving the mail. I tried a tracert to his mail server and the request just times out and goes no where. Is it safe to say that this is on their side?