help in mail server

[johnnet]

καλημερα εχω ενα προβλημα με τον mailserver δεν μπορω να στηλω και εχω αυτο το λαθος

The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'migrate2linux at lists.hellug.gr'. Subject 'Re: help', Account: 'web', Server: 'mail.mydomain.gr', Protocol: SMTP, Server Response: '550 5.7.1 <migrate2linux at lists.hellug.gr>... Relaying denied', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'migrate2linux at lists.hellug.gr'. Subject 'Re: help', Account: 'web', Server: 'mail.mydomain.gr, Protocol: SMTP, Server Response: '550 5.7.1 <migrate2linux at lists.hellug.gr>... Relaying denied', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79
ενω μπορω και περνω απο παντου 
καποια βοηθεια, ευχαριστω
                  Ioannis Zontos
           Network Administrator
                  C & C Group
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.hellug.gr/pipermail/migrate2linux/attachments/20030819/c8656f61/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 1303 bytes
Desc: not available
URL: <http://lists.hellug.gr/pipermail/migrate2linux/attachments/20030819/c8656f61/attachment.gif>