c# - FormAuthentication .ASPXAUTH cookie showing null after few moments in ASP.NET MVC -

i have implemented formauthentication in asp.net mvc 5 , create formsauthenticationticket on login , creates after few moments cookie showing in browser in application it's getting null.

please solve issue.

any appreciated thanks

login form

  public actionresult login([bind(include = "username, password")] loginmodel loginmodel, string returnurl)     {         if (modelstate.isvalid)         {             egov_users egov_users = db.egov_users                 .where(p => p.usertype.type != "o" && p.username == loginmodel.username)                 .firstordefault();              if (egov_users == null)             {                 modelstate.addmodelerror("", "invalid username");                 return view();             }             else             {                 if (egov_users.password != loginmodel.password)                 {                     modelstate.addmodelerror("", "invalid password");                     return view();                 }                  var logindetail = new logindetails();                 var serializer = new javascriptserializer();                  logindetail.userid = egov_users.userid;                 logindetail.username = egov_users.username;                 logindetail.firstname = egov_users.firstname;                 logindetail.lastname = egov_users.lastname;                  var userdata = serializeuserinfointernal(logindetail);                  formsauthentication.setauthcookie(logindetail.username, false);                  var cookie = formsauthentication.getauthcookie(                            formsauthentication.formscookiename, false);                  var ticket = formsauthentication.decrypt(cookie.value);                  var durationinhours = 8;                 formsauthenticationticket newticket = new formsauthenticationticket(                     ticket.version,                     logindetail.username,                     datetime.now,                       datetime.now.addhours(durationinhours),                     true,                     userdata);                  // encrypt ticket.                 string encticket = formsauthentication.encrypt(newticket);                  cookie.value = encticket;                 response.cookies.add(cookie);                  int cookiesize = system.text.utf8encoding.utf8.getbytecount(cookie.values.tostring());                 session["cookiesize"] = cookiesize;                 if (string.isnullorempty(returnurl))                 {                     return redirecttoaction("index", "users");                 }             }         }          return redirecttoaction("login", "login");     } 

global asax

 protected void application_postauthenticaterequest()     {         var ticket = getticketfromcurrentcookie();         if (ticket == null)         {             global.writelog("application_postauthenticaterequest", "ticket becomes null");             return;         }         var user = deserializeuserinfointernal(ticket.name, ticket.userdata);         if (user == null)         {             return;         }         var principal = new appuserprincipal(user);         httpcontext.current.user = principal;     }     private static formsauthenticationticket getticketfromcurrentcookie()     {         var cookie = httpcontext.current.request.cookies[formsauthentication.formscookiename];          if (cookie == null)         {             global.writelog("getticketfromcurrentcookie", "cookie becomes null");             return null;         }          var ticket = formsauthentication.decrypt(cookie.value);         return ticket;     }     static logindetails deserializeuserinfointernal(string name, string userdata)     {         var deserialize = new javascriptserializer();          var logindetails = deserialize.deserialize<logindetails>(userdata);          return logindetails;     }