c# - Inproc Session lost in same page asp.net

Question

I had to recently publish an Asp.NET application(Target framework 4.5.1) into IIS 10.

I am creating a Session variable in Page_Load method. No events happen except a button click to select where it needs to redirected. But when you click on the button, already the session is lost.

protected void Page_Load(object sender, EventArgs e)
{
     if (!IsPostBack)
     {
          Session["Token"] = "abc";
     }
}

protected void btn_Click(object sender, EventArgs e)    
{
     Response.Write(Session["Token"].ToString());
}

Now, the btn_Click throws error saying Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.NullReferenceException: Object reference not set to an instance of an object..

I changed my session to have cookieSameSite="None". But still it does not store the session in the page.

<sessionState mode="InProc" timeout="60" cookieSameSite="None" />

Is there any setting I have to do in IIS so my Session does not get removed/reset inside the page itself?

Answer 1

等待大神答复