Article ID: 290808 - View products that this article applies to.
This article was previously published under Q290808
You can send outbound SMTP mail from a Microsoft Outlook client but cannot send outbound SMTP mail from a Microsoft Outlook Express client, and the following non-delivery report (NDR) is generated.
The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'firstname.lastname@example.org'. Subject 'Re: test', Account: 'mail.domain.com', Server: 'mail.domain.com', Protocol: SMTP, Server Response: '550 5.7.1 Unable to relay for email@example.com', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79
Exchange Server 5.5 has an option to require credentials when connecting to the Internet Mail Service. Exchange 2000 also provides this option with SMTP.
Use one of the three options below.
NOTE: Do not combine the first option with either the second or third option.