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OE6 error sent to external domain

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  • OE6 error sent to external domain

    I just perform a Exch2010 installation with coexistence with Exch2003.

    Everything seem to be fine at the moment.

    In this org. have several user still using OE 6.


    If use OE6 send email to external domain result in "The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was [email protected]'. Subject 'a', Account: 'Exadmin', Server: '', Protocol: SMTP, Server Response: '550 5.7.1 Unable to relay', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79"

    My Outgoing Server requires authentication is tick--> Use same as my incoming.

    For troubleshooting, one the same PC, if using MS Outlook able to send the same email to external without error.

    Why if use Outlook OK but use OE6 errors?

  • #2
    Re: OE6 error sent to external domain

    Outlook is most likely using the RPC protocol to talk to your Exchange server.

    Outlook Express can only use SMTP to send emails. For Outlook Express to send emails externally it will need to use a SMTP server that is configured to relay externally. Generally not a recommended way of doing it, but you'll need to enable SMTP relaying on your Exchange server or whichever server you have configured as SMTP in Outlook Express.

    Of course this relaying should only be configured on a local interface, you don't want people externally to relay through your Exchange server as well.

    Just upgrade to Outlook, much better option.


    • #3
      Re: OE6 error sent to external domain

      For exchange we are still using POP to retrieve email.
      I notice that Exch 2010 doestn't have smtp services like the one in Exch2003.
      Do i need to create special smtp connector at HUB transport?


      • #4
        Re: OE6 error sent to external domain

        Yes you'll need to create a "Receive Connector" under Server Configuration - Hub Transport

        Or set the SMTP server back to the old Exchange 2003 server which probably already has something similar set up.


        • #5
          Re: OE6 error sent to external domain

          There is no need to create any connectors.
          The CLIENT connector is setup to do authenticated relaying. You just need to use TLS to connect.
          You also cannot enable the option to use the same credentials as incoming. You need to choose specific credentials and enter them in the format of domain\username.

          I would also encourage you to move to Outlook Anywhere - Outlook Express 6 and POP in general is a poor protocol which has no place in a corporate network.

          Simon Butler
          Exchange MVP

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