Forms Authentication reseting on every postback

I have a web site that works fine on the server.  I purchased a new domain and set that up on my web server and set the home directory on to the server to the same location as the site that works. 
However, my forms authentication ticket is being recreated on every page post back.  Is there some setting in IIS that I'm missing under the new domain(IP)?  If I access the site under one domain the ticket is saved and tracked fine.  When I access it from the second domain (same home directory as first domain) the ticket is lost on postback. 
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