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cPanel forwarder - "550 unauthorized interface" error

Discussion in 'E-mail Discussion' started by woodp5, Jun 9, 2010.

  1. woodp5

    woodp5 Member

    Feb 19, 2007
    Likes Received:
    Trophy Points:
    Central California, USA
    Email to a particular individual on the AT&T network works fine. ( and are part of AT&T's network.)

    Email via a cpanel forwarders to the same individual bounces with the following error:

    (ultimately generated from
    SMTP error from remote mail server after initial connection:
    host []: 550 unauthorized interface for on kcin01

    A page at the AT&T Website suggests a 550 unauthorized interface error as "The sending system is not recognized as a valid source of e-mail."

    Why is a cPanel forwarder not being recognized as a valid source of email?

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