Has anyone ever seen this message? I am using Exchange 2003 and all has been working. All of a sudden users are getting NDR's. I have been looking at the MS site for answers but dont see any. I also wonder if this could have something to do with ISA server that outgoing mail passes through. Any ideas?? Thanks TD Your message did not reach some or all of the intended recipients. Subject: FW: quote please Sent: 2/24/2005 1:39 PM The following recipient(s) could not be reached: 'abcd@*****.com' on 2/24/2005 1:42 PM There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. <saltex01.abc.ca #5.5.0 smtp;500 Error mail not terminated with '.'>