Relaying denied. Proper authentication required error message

I have SBS2003 server installed and receive this error when sending from and Outlook client.

  You do not have permission to send to this recipient.  For assistance, contact your system administrator.
            <SERVER.kass.local #5.7.1 smtp;550 5.7.1 <>... Relaying denied. Proper authentication required.>

The email client has both a Exchange Server setup and a POP3 setup in their client. If Exchange server is selected as the account to send this error is received. If the POP3 account is selected it goes out fine.

Any help would be appreciated.

Tim O'Neill
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Open ESM and go to the Proerties of default smtp virtual server -->Access--> relay-->and make sure that there is a check on "Allow all computers......."
Also, go to Delivery --> Advance and change your fqdn.
NEKeyITAuthor Commented:
the box is checked for allowing clients who authenticate to send and I do have the fqdn. These did not change the error
How are you clients configured?

MAPI or using POP3/SMTP?

That error message doesn't look like an Exchange message to me, so it is coming from outside.
When you configured SBS, did you tell it to use a smart host - perhaps your ISP? If so you may have to configure authentication on the SBS Connector to allow the email messages to go through.

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NEKeyITAuthor Commented:
What I am trying to accomplish is not having the client with a POP3 connector and just have a MAPI for exchange. I added a pop3 connector on the Exchange server to pull email since Exchange's did not work pulling mail. My clients are just having problems with both the MAPI and POP3 on the client. If I remove the pop3 from the client and just have Exchange I receive the error. I can't figure out why Exchange will not deliver email with the SMTP connector.
There seems to be some confusion on the technologies here...

Forget about the Exchange server for a moment...

When you configure an Outlook client, are you configuring the client to use Exchange server, or connect via POP3/SMTP and entering the Exchange server's details as the POP3 and SMTP server to be used?

How do the clients receive new email? Do they collect it from the ISP directly, or does the Exchange server do that using the POP3 connector?

NEKeyITAuthor Commented:
The clients are configured with an Exchange and Pop3 connector. The POP3 is configured to pull external email. When you configure the client you have to select a default! If exchange is set as the default the email goes out and the error happens.
If the client selects the accounts next to the send button and selects the pop3 the mail goes out. If we select the Pop3 as the default all external emails go out but then internal email via exchange fails.
With Exchange set as the default I suspect that you have configured an SMTP Connector on the Exchange server, but your ISP requires authentication for sending. You will need to adjust the SMTP Connector to authenticate.
What many ISPs do is require authentication, but if you have just authenticated for POP3 collection you don't need to authenticate again for the SMTP delivery. The Exchange server isn't doing POP3 collection so needs to authenticate.

If you are on any kind of permanent internet connection then your best option would be get switch to SMTP delivery and get all of your email delivered directly to the Exchange server. That will get round these problems with which server is used for sending the email.


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