Iterations page error (at method GetWorkItemsForIteration)

There’s another error on “Iterations”.
at method: GetWorkItemsForIteration
Message: Object reference not set to an instance of an object.

StackTrace:

at TimetrackerOnline.JointCodebase.BusinessLayer.Context.Services.IterationBacklogService.GetWorkItemsForIteration(VsoTokenModel tokenModel, BacklogParameters parameters, ProcessSettingsModel settings) in C:\BuildAgent\_work\13\s\TimetrackerOnline\TimetrackerOnline.BusinessLayer\Context\Services\IterationBacklogService.cs:line 354

at TimetrackerOnline.JointCodebase.BusinessLayer.Context.Services.IterationBacklogService.GetBacklogItemTree(VsoTokenModel tokenModel, BacklogParameters parameters, ProcessSettingsModel settings) in C:\BuildAgent\_work\13\s\TimetrackerOnline\TimetrackerOnline.BusinessLayer\Context\Services\IterationBacklogService.cs:line 189

at TimetrackerOnline.JointCodebase.BusinessLayer.Context.Services.IterationBacklogService.GetBacklog(VsoTokenModel tokenModel, BacklogParameters parameters) in C:\BuildAgent\_work\13\s\TimetrackerOnline\TimetrackerOnline.BusinessLayer\Context\Services\IterationBacklogService.cs:line 115

at TimetrackerOnline.Controllers.IterationsController.GetBacklog(String urlHash, Guid teamId, Guid projectId, Boolean iterationDatesFilterOn, Boolean movedItemsFilterOn) in C:\BuildAgent\_work\13\s\TimetrackerOnline\TimetrackerOnline.Web\Controllers\IterationsController.cs:line 89

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.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState)

at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult)

at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult)

at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d()

at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f()