Login error: Object reference not set to an instance of an object.

022-05-12 17:33:31,238 [11] ERROR SpartezSoftware.Synchronizer.Controllers.AccountController - Fatal error requesting POST http://localhost/tfs-jira-synchronizer/Account/LogOn?ReturnUrl=%2ftfs-jira-synchronizer
System.NullReferenceException: Object reference not set to an instance of an object.
   at SpartezSoftware.Synchronizer.Controllers.AccountController.LogOn(LogOnModel model, String returnUrl, CancellationToken cancellationToken)
   at lambda_method(Closure , ControllerBase , Object[] )
   at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
   at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass15.<InvokeActionMethodWithFilters>b__12()
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
   at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)