Problem installing campsite

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Hi all,

We are installing campsite 2.1.7-rc2 on amin's server. Everything checks
out during installation except the EVENT_HANDLERS module. When we define
it to localhost or the IP address,we get:

Testing EVELT_HANDLERS configuration...ERROR
Error sending message: 552 sorry, your envelope sender domain must exist
(#5.7.1)

We already tried localhost and IP address of the server but ended up with
the same error.

thanks for the help in advance :)

Raed

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