I log in with FormsAuthentication. Remember Me is on. I added 6 months for the expiration date. After logging in, I also check cookies and see that the cookie is saved. Expire date is recorded 6 months later.
It logs in normally, everything works fine, but when I try to log in the next day, it doesn’t remember me and sends me back to the login screen.

I added the following line to the login page controller and I am checking cookies:
HttpCookie authCookie = HttpContext.Request.Cookies[FormsAuthentication.FormsCookieName];

authCookie always returns null the next day. When I go to developer tools from the browser and check the cookie, I see that the cookie is present.
Why does HttpContext.Request.Cookies[FormsAuthentication.FormsCookieName] return null?

(I defined it as follows in Web Config: )

Here is the code at Login/Index Controller :

HttpCookie authCookie = HttpContext.Request.Cookies[FormsAuthentication.FormsCookieName];
if (authCookie != null)
{
FormsAuthenticationTicket authTicket = FormsAuthentication.Decrypt(authCookie.Value);
if (authTicket == null || authTicket.Expired)
{
return View();
}
else
{
string _userData = authTicket.UserData;
string code = _userData;

                var rs = db.User.Where(x => x.Code == code).FirstOrDefault();
                if (rs != null)
                {
                    return RedirectToAction("Index", "Home");
                }
                else
                {
                    return View();
                }
            }
        }
        else
        {
            return View();

            }

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I tried to change slidingExpiration to false but didn’t work.