Hi

that problem 's solved now .
Question: How did you solve it?


Within the SMTP rfc[1], 550 is a generic error code for a "RCPT Failure"
reply. Usually, the mail server specifies the failure with more details,
e.g. "Unable to relay for ...".

In this particular case, the error is most likely caused because the mail server
did not recognise you as an authorised user.

You tried to use the mail-server[2,3] to send an email to an external
email-address without proper authentication (if you would be able
to do so, the mail-server would be known as an "open relay").
This is the reason for my question. I would like to avoid your
mail server to be blacklisted[4].


Cheers

/edit: your mail server needs SMTP (delivery) outgoing and incoming (Port 25)
In addition, POP3 (Port 110) may be needed.
If you are behind a router, make sure that the necessary ports are forwarded
to your mail server. But still, be sure you understand what you are doing
before opening the port to the public.


[1] http://www.ietf.org/rfc/rfc0821.txt
[2] http://www.microsoft.com/technet/pro...87a2b88f2.mspx
[3] http://support.microsoft.com/kb/q230235/
[4] http://www.ordb.org/