Posting Not Allowed

Hello, I have been using tin for a short period of time and have been
having the problem of not being able to post to the newsgroups.  I have
looked over the man page and googled and so far have not been able to
find a solution.  I know that it is not a problem with my newsgroup
server because I can post just fine when I use Pan (a graphical
newsgroup reader).  It's when I use tin that I get a message on startup
saying:
tin 1.6.2 release 20030910 ("Pabbay") [UNIX] (c) Copyright 1991-2003
Iain Lea.
*** Posting not allowed ***
...
I don't know what else to do at this point.  Any responses to my problem
would be appreciated, thank you.
-- 
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