Outlook Express - SMTP

I work on a Computer running Outlook Express. I'm new in this Company... unfortunately others use Pegasus Mail, etc. I really want to use Outlook.

Question: Pegasus mail can send emais with SMTP to local and external sites. Pmail has the same settings as my Outlook. Te SMTP site is ns.x.x, and the POP3 is mail.x.x, so they're not the same. Whenever I send an email from Outlook Express to an external friend, I got an error message: relaying denied. If I do this with Pegasus mail, it succeeds. Both of them works for local addresses.
I tried it with 'telnet ns 25', probing all of the commands, and flows, but I always get relaying denied.

Telnet 25 says the server is ESMTP Sendmail 8.9.3/8.9.3.

What can I do for my Outlook Express ?

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Could it possibly be that the SMTP server is requiring POP3 authentication before sending? It's becoming more popular...
steweAuthor Commented:
How can I set it up in Outlook ? And in Outlook Express ?
And I wrote, the 2 machine is not the same. Is it matter ?
It's not something that Outlook supports internally. Right now the usual solution is to use an external utility to poll the mailbox just prior to sending. You can find a good one here:

You should test out the theory by having Outlook/OE poll your mailbox then try to send and see if it works.
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steweAuthor Commented:
Doesn't work.
I still can't send and the error is the same...
See if any of the advice here helps (it's about Outlook 2000 but some of it may apply to OE):

You can also get this article by sending an E-mail with a subject of "Q214402" (without the quotes) to mshelp@microsoft.com.

This link should automate that for you:

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steweAuthor Commented:
Thanks, I really figured out what to do with our administrators.

They found some options to set in their Linux SMTP server, using the infos.

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