Exchange 2003.. Outside vendor created an application for us that does order entries and sends out Email confirmations using SMTP. Many Emails are getting bounced back with this message: You do not have permission to send to this recipient. For assistance, contact your system administrator.
< (OUR EMAIL SERVER.OUR DOMAIN) #5.7.1 smtp;550 5.7.1 < (EMAILADDRESS)>... Relaying denied>
App vendor thinks the relay restrictions are to blame. I have allowed the workstation range of IP addresses, the web server IP, and checked the box that allows anybody who successfully authenticates....to relay. They did mention one odd thing....Emails that go to addresses already in our global list of contacts don't seem to get bounced back, but ones that aren't do. Is there some kind of relay restriction based on membership in an address list?
My suspicion is that his app just isn't authenticating properly, if at all, but he insists that the exchange server settings need fixing. Not sure where to look next. Any ideas?