Stage, Long for HSPL, Partner login

In Partner login, onboard module, if from menu, Customizer >> Employee Screen Configuration >> Change Approval selected, server error occurs.

PFA screen shot and error log

Exception : Object reference not set to an instance of an object.
App Error Log : -
Employee ID : 0
Action Name : ChangeApproval
Model : System.Web.Mvc.HandleErrorInfo
Controller : Customization
Web Error Log : at WORKTERRA.Shared.WORKTERRAControllerWebTier.GetData(ObjectType I_objectType, Hashtable I_criteria, Object I_context, Boolean I_mode, Boolean I_needCollection)
at WORKTERRA.Shared.Areas.Customization.Models.ChangeApprovalModel.PopulateChangeApprovalDetail()
at WORKTERRA.Shared.Areas.Customization.Controllers.CustomizationController.ChangeApproval()
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.b_12()
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)