ok my scenario:
i use postfix as my MTA, in my lan i can, check with outlook express(can send emails and receive emails from my lan and from internet...), i have squirrel mail installed and too can send mail and receive emails ok, but when i try configure Outlook Express in the home of my boos/chief i cant send emails because these error (NOTE can receive, but cant send):

The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'jamiguel77@hotmail.com'. Subject 'Hola', Account: 'MyAccount', Server: 'dns.grupolanortenita.com', Protocol: SMTP, Server Response: '554 <jamiguel77@hotmail.com>: Relay access denied', Port: 25, Secure(SSL): No, Server Error: 554, Error Number: 0x800CCC79


any advice? what other info need type here for can help me yours, thanks

seems that you have set dns.grupolanortenita.com as realyhost for all outgoing mails.
but this server doesn't allow mail from you to be realy'd.

either choose another relayserver (your isp's should have one that realys all mail for all clients)
or do it without realyhost.

i administrate my own server, my isp i can acces the server, what change or settings need for work properly my server?


thanks

well usually smtp realy host is mail.yourispdomainname.tdl or something, but you should check it from yours isp support center or somehting