[IMail Forum] Help SMTP Authentication

[Banet LLC]

We are using v6.05a and have several hundred customers using Outlook Express that are unable to send mail. To the best of my knowledge all of these customers have server requires authentication set up.   On the server side we have SMTP Security set for "relay mail for". We have the start of our IP block of addresses listed. Although we have tried it without anything here being listed.   The error message that all of our clients are getting is:   "The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was '[EMAIL PROTECTED]' . Subject "Sorry' Account: 'mail.yourdomain.com', Server: ' mail.yourdomain.com', Protocol: SMTP, Server Response: '550 not local host abc.com, not a gateway, Port 25, Secure (SSL): No, Server Error: 550, Error Number: 0x800CCC79"   Thank you for anyone that can help me to solve this problem.   Howard Martin