Access to Backlog unavailable post TFS 2017 RC1 upgrade - tfs

Question

The tfs backlog page throws the following error : "TF400898: An Internal Error Occured." after upgrading to TFS 2017 RC1 from TFS 2015. All the other contents are in tact (ie Code, Build and Test). This error occurs for all the team projects in the Team Collection. Upgrade to tfs 2017 RC1 was successful without any errors.
Error logged in event viewer:
TF53010: The following error has occurred in a Team Foundation component or extension:
Date (UTC): 1/30/2017 12:47:55 PM
Machine: TFS01
Application Domain: /LM/W3SVC/2/ROOT/tfs-1-131302443521960468
Assembly: Microsoft.TeamFoundation.Framework.Server, Version=15.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a; v4.0.30319
Service Host: 4fc1f4bf-8005-4244-a66c-c57edf4df7f1 (<Team Project Collection>)
Process Details:
Process Name: w3wp
Process Id: 18288
Thread Id: 36708
Account name: <Domain>\<User>
Detailed Message: TF30065: An unhandled exception occurred.
Web Request Details
Url: http://<TfsServer>:8080/tfs/<TeamProjectCollection>/<TeamProject>/Application/_backlogs [method: GET]
User Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.3; WOW64; Trident/7.0; .NET4.0E; .NET4.0C; .NET CLR 3.5.30729; .NET CLR 2.0.50727; .NET CLR 3.0.30729; InfoPath.3)
Headers: not available
Path: /tfs/<TeamProjectCollection>/<TeamProject>/Application/_backlogs
Local Request: True
Host Address: fe80::a8d5:ecb7:9ff9:640c%13
User: <Domain>\<User> [authentication type: Negotiate]
Exception Message: Object reference not set to an instance of an object. (type NullReferenceException)
Exception Stack Trace: at Microsoft.TeamFoundation.Server.WebAccess.WorkItemTracking.Common.BacklogConfigurationService.<>c__DisplayClass1_0.<GetBacklogConfiguration>b__0()
at Microsoft.TeamFoundation.Framework.Server.VssRequestContextExtensions.TraceBlock[T](IVssRequestContext requestContext, Int32 enterTracepoint, Int32 leaveTracepoint, Int32 exceptionTracepoint, String area, String layer, String methodName, Func`1 action)
at Microsoft.TeamFoundation.Server.WebAccess.WorkItemTracking.Common.BacklogConfigurationService.GetBacklogConfiguration(IVssRequestContext requestContext, Guid projectId, TeamFoundationTeam team, Boolean validateProcessConfig)
at Microsoft.TeamFoundation.Agile.Server.AgileSettings..ctor(IVssRequestContext requestContext, CommonStructureProjectInfo project, TeamFoundationTeam team)
at Microsoft.TeamFoundation.Server.WebAccess.Agile.AgileAreaController.get_Settings()
at Microsoft.TeamFoundation.Server.WebAccess.Agile.BacklogsController.get_RequestBacklogContext()
at Microsoft.TeamFoundation.Server.WebAccess.Agile.BacklogsController.Index(String level, Nullable`1 showParents)
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.<>c__DisplayClass42.<BeginInvokeSynchronousActionMethod>b__41()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass37.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass25.<>c__DisplayClass2a.<BeginInvokeAction>b__20()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass25.<BeginInvokeAction>b__22(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult)
at System.Web.Mvc.Controller.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar)
at System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar)
at System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult)
at System.Web.Mvc.MvcHandler.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar)
at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Answer 1

If the upgrade was successful without any errors. Then this kind of issue may related to the configuration.
You could try re-running the configuration wizard for the team project to fix the issue. How to please refer this tutorial: Configure features after an upgrade