为什么outlookexpress 发不出email呢？信息 见内..2005-10-09 04:19:55

The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was sdfs@asd.com'. Subject 'questions', Account: 'imap.xxx.edu (1)', Server: 'smtp.xxx.edu', Protocol: SMTP, Server Response: '550 ... Relaying denied', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79

接受时没问题，发到我自己的信箱里也没问题，发到本学校的email adress都没问题。
那位expert知道是什么问题啊？

发到非本学校的email adress的统统被拒，为什么？

school blocked smtp port:25

I changed it already. but 3xs.