Getting "Error occurred during a cryptographic operation"

Question

As I hosted my application in plesk cloud server and everything is fine but if I sit screen ideally for 10 min then it will show the error

 

Error occurred during a cryptographic operation.

 

I did not understand why it is showing error, please help me. 

 

Here is my global.ashx file code and controller code

protected void Application_PostAuthenticateRequest(Object sender, EventArgs e)
       {
           //HttpCookie authCookie = Context.Request.Cookies[FormsAuthentication.FormsCookieName];
           HttpCookie authCookie = HttpContext.Current.Request.Cookies[FormsAuthentication.FormsCookieName];
           if (authCookie != null)
           {
               FormsAuthenticationTicket authTicket = FormsAuthentication.Decrypt(authCookie.Value);
               LoginUserViewModel serializeModel = JsonConvert.DeserializeObject(authTicket.UserData);
               CustomPrincipal newUser = new CustomPrincipal(authTicket.Name);
               newUser.Id = serializeModel.Id;
               newUser.Email = serializeModel.Email;
               //newUser.Password = serializeModel.Password;
               newUser.FullName = serializeModel.FullName;
               newUser.FirstName = serializeModel.FirstName;
               newUser.LastName = serializeModel.LastName;
               newUser.Roles = serializeModel.Roles;
               HttpContext.Current.User = newUser;
           }
       }

namespace WebApp.Controllers
{
    public class AccountController : Controller
    {
        // GET: Account
        IUserRepository repo_user;

        public AccountController(IUserRepository _repo_user)
        {
            repo_user = _repo_user;
        }
        public ActionResult Login()
        {
            return View();
        }
        public ActionResult UnAuthorize()
        {
            return View();
        }

        [HttpPost]
        public ActionResult Login(LoginViewModel model)
        {
            if (ModelState.IsValid)
            {
                //UserViewModel user = repo_user.ValidateUser(model);
                LoginUserViewModel user = repo_user.ValidateUser(model);
                if (user != null)
                {
                    string data = JsonConvert.SerializeObject(user);

                    FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(1, user.Email, DateTime.Now, DateTime.Now.AddMinutes(FormsAuthentication.Timeout.TotalMinutes), false, data, FormsAuthentication.FormsCookiePath);
                    string encTicket = FormsAuthentication.Encrypt(ticket);
                    HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName, encTicket);
                    Response.Cookies.Add(cookie);

                    if (user.Roles.Contains("Admin"))
                    {
                        return RedirectToAction("Index", "Home", new { area = "Admin" });
                    }
                    else if (user.Roles.Contains("Company"))
                    {
                        return RedirectToAction("Index", "Home", new { area = "Company" });
                    }
                    else if (user.Roles.Contains("User"))
                    {
                        return RedirectToAction("Index", "Home", new { area = "User" });
                    }
                    else if (user.Roles.Contains("Franchisee"))
                    {
                        return RedirectToAction("Index", "Home", new { area = "Franchisee" });
                    }
                }
                else
                {
                    TempData["UserLogin"] = " Userid or Password does not exist, please try with other credential";
                }
            }
            return View();
        }
        public ActionResult SignOut()
        {
            FormsAuthentication.SignOut();
            return RedirectToAction("Login");
        }
    }
}