We have a recurring issue where one of our contacts is in an email chain and they are replying to emails from us and some go through to us and some get bounced with the below error. Is this on my end, or theirs? How can we resolve this? It looks like they have Postini -- could this be causing issues?
Your message did not reach some or all of the intended recipients. Subject: RE: Sent: 04/28/2009 4:35 PM The following recipient(s) could not be reached:
email@example.com on 4/28/2009 4:36 PM
There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
<EX-021.mail.navisite.com #5.5.0 smtp;550 sorry, no mailbox here by that name. (#5.7.17)>