URGENT ISSUE - #5.5.0 smtp;550 Relay not permitted

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We are having an issue with our exchange 2003/sp2 application. We have
one co-worker that is parttime. He asked that we forward all email
sent to our local domain to his other business account, which we are
trying to do. This is the issue: #5.5.0 smtp;550 Relay not permitted.

We set his local account to forward all emali to his other email
address and get a #5.5.0 smtp;550 Relay not permitted each time we
send an email to the local account.

We are running SBS 2003/SP1. We did just reload the server. Is there
somthing I did not configure correctly? I have been to DNSReport and
have found that we are running perfectly. Also, we are not listed as a
spam domain, I checked that also.

Please help.

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