using mew in emacs21.3

[xueruini]

Hello, all
 I am using mew with emacs21.3 on winxp. Mew can receive my
mails well, but when I want to send a mail, these errors occurs:

***********************************************************
Connecting to the SMTP server...done
Sending in background...
1.wrk has been queued to +queue/1 (553 host denies relay (eyou mta)
)
(New file)
Wrote f:/EmacsConf/Mail/draft/1
Draft is prepared
Auto-saving...done
Really send this message? (y or n) 
Wrote f:/EmacsConf/Mail/draft/1
Making a message...done
Connecting to the SMTP server...done
Sending in background...
2.wrk has been queued to +queue/2 (553 host denies relay (eyou mta)
)
Making completion list... [2 times]
(New file)
Wrote f:/EmacsConf/Mail/draft/1
*******************************************

This is a part of the error messages. I do not know what had happened, 
may be the smtp authentication? how to set it?