Regarding Webservice, NHibernate and their sessions

[TigrouMeow]

Hello,

I'm trying to make a "clean" webservice, using Nhibernate. I'm facing
some issues, but i'm quite the beginner with that kind of system. When
there are more than 2 clients connected on my webservice, i get
errors. It seems that the connection is dropped. Here is what i get
in theWinforms application using the Webservice :

Error = {"The underlying connection was closed: An unexpected error occurred
on a receive."}

and sometimes :

[System.Net.WebException] = {"The request failed with HTTP status 403:
Access Forbidden."}

In my webservices, I don't catch any exceptions.

My webservice is working like this : for each "Webservice" session I have,
I create a "NHibernate" session. Is it a good approach ? And when the
users are disconnecting from my webservice without warning, does the
garbage collector manage the "ghost" Nhibernate sessions ?

I also have a static class that manages a static ISessionFactory, and that's
the class I use to create new NHibernate sessions for new connected
users. Is this correct too ?

Thanks in advance :)