用python3.5写邮件是报错误

from email.mime.text import MIMEText
import smtplib

msg = MIMEText('你是个大笨蛋','plain','utf-8')

from_addr = input('From:')
password = input('Password:')

to_addr = input('To:')

smtp_server = input('SMTP server')

server = smtplib.SMTP(smtp_server,25)
server.set_debuglevel(1)
server.login(from_addr,password)
server.sendmail(from_addr,[to_addr],msg.as_string())
server.quit()
请问为啥报错误？smtplib.SMTPDataError:(554...........)

http://blog.csdn.net/littlethunder/article/details/29355403