ASP.NET站点无意中共享登录cookie

I have a few ASP.NET sites running on one IIS server, of course using different ports. The sites allow for logging in via forms authentication. Session state is stored on a local state server. My problem is that when a user logs into one sites and then navigates to another, they get an exception from the second site and have to close/reopen their web browser to be able to access it. My guess is that the cookie from the first site is making it appear that they're logged in on the second one as well (though I could be completely wrong about this). I have a few ASP.NET sites running on one IIS s