Cannot Receive emails from certain people!

[Teknet]

Hi

Around two months ago one of our clients mysteriously started bein
unable to receive emails from around 4 users they could still receiv
emails from everyone else , so we thought it was a mail serve
problem.
So we moved the emails to a new server and there still having the sam
issues. We have tried sending emails through AOL,Hotmail,Yahoo, O2 an
our own email and they all go through fine , but these for compine
which just happen to be there major clients keep getting this error-

Your message did not reach some or all of the intended recipients.
Subject: RE: email
Sent: 25/02/2010 09:53
The following recipient(s) cannot be reached:
user@*********co.uk on 25/02/2010 09:54
The e-mail account does not exist at the organization this message wa
sent to. Check the e-mail address, or contact the recipient directly t
find out the correct address.
<hesa06uker.he.local #5.1.1>

Any ideas why most emails work but some don’t , as the mailbo
obviously exists??

Many thank

 

[Brian Tillman [MVP-Outlook]]

Your message did not reach some or all of the intended recipients.
Subject: RE: email
Sent: 25/02/2010 09:53
The following recipient(s) cannot be reached:
user@*********co.uk on 25/02/2010 09:54
The e-mail account does not exist at the organization this message was
sent to. Check the e-mail address, or contact the recipient directly to
find out the correct address.
<hesa06uker.he.local #5.1.1>

Any ideas why most emails work but some dont , as the mailbox
obviously exists??

That's a server-side message and there's nothing in Outlook that can change
it. If the server that handles the recipient's mailbox is saying the mailbox
doesn't exist, the people sho manage that server will need to address the
problem.