Rt-3-0-0 and trouble creating tickets

I upgraded to rt-3-0-0 and I am now having trouble creating tickets via
email. The error that root receives in an email message is:

RT could not load a valid user, and RT’s configuration does not allow
for the creation of a new user for your email.

What could be causing this error?

Thanks,

Joseph W. Breu, CCNA fax : +1.319.266.8158
Senior Network Administrator url : http://www.cfu.net
Cedar Falls Utilities

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	              -- Wm. Shakespeare