SMTPlib Sender Refused?

[erikcw]

Hi,

I'm trying to send an email message with python, and I'm getting this
error:

Traceback (most recent call last):
  File "wa.py", line 430, in ?
    main()
  File "wa.py", line 425, in main
    smtp.sendmail(fromaddr, to, msg.encode('utf-8'))
  File "/usr/local/lib/python2.4/smtplib.py", line 680, in sendmail
    raise SMTPSenderRefused(code, resp, from_addr)
smtplib.SMTPSenderRefused: (503, 'sender already given',
'me at mydomain.com')

What is causing this?

Thanks!
Erik