Flexi Task: Error in task: object reference not set to an instance of an object

[jacobarn]

Hello,

I seem to be having a problem that we can't figure out. I have a list for our locations to submit request to create product codes. There are three levels of approval and the first two levels can both submit a request. The problem is, when the lowest level submits the request to go to the second level, I get the Error in task message. Restarting the workflow manually does not do this, only when the workflow starts automatically on creation of the list item. If the second level submits there is no error.

At first I thought it was a permission issue similar to the this post HERE because the email reminder took them to that something went wrong page. However I set everyone's permissions to the same Edit level and I still have this problem. The only difference between the first level and second level is the first level has to choose from a people box who to send to at the second level. However this is working as shown in the screen shot as well.

Has anyone else had this problem or could possible suggest where I can go to find what the error is? I don't personally have access to the central admin and those who do are not as familiar with Nintex yet as they are new so I could use some help at the very least with suggestions on how to troubleshoot this.

Thanks

[dellasiega]

hello i have a same problem have ou set up it?

[ignasitt]

I'm having the same errror from a long time ago. I tried everything: Reduce the number of actions of the workflow, convert loops into status machine (at least I can restart workflow at second level of validation), add pause for 5 minutes after changing permissions actions, review the "Commit pending changes" schema, ensure there are no workflows starting on "workflow Task list" (I thought some tasks were overlapping starting several workflows on the same time), I checked permissions a lot of times.... Nothing.

I even opened a case with Nintex Support, but I had no way to fix this, their answer were so vague...

So I'm restarting manually about 20/30 workflows manually every day...

Please, share if you are able to find a solid solution to this problem.

Best regards.

[jacobarn]

I have also opened a case with Nintex Support...spent two hours trying to replicate it on a dev environment with no luck so they are "looking into it".

[ignasitt]

Do you have multiple Front-End Servers (WFE) in your farm?

We had 2 of them, but today we full detached the second one in our farm. So far we had 0 errors in 7 hours (Usually we should have about 10 in this period of time). It's quite soon to take conclussions, but maybe it can explain why we had aleatory errors (if the traffic was redirected to other WFE --> error, if not --> OK)... I will let you know the results in a wider period of time.

[ignasitt]

Sorry, after a first day without errors we went back to the same situation. Maybe it's something related to SharePoint boundries or workflow engine overload. I'm not sure yet. Still searching. Please, let us know if there's something new on your side.

[jacobarn]

Nintex came back and asked me to do this, I'm traveling and can't get to it quickly but maybe you can or have tried this:

In IE, open the Developer tools and run a clean debugger when loading the Assign a Task configuration. Let me know if there are any errors like "Object doesn't support property or method" or "Cannot deserialize empty string."

Thanks

[ignasitt]

Hi Jacob, I don't know exactly what it means   "loading the Assign a Task configuration"  if it means in the Nintex Workflow designer, editing the Workflow, it has no sense due the configuration is perfectly correct. It's only on the second validation stage (sometimes higher) that happens. If it means opening the validation form task (created from Nintex Forms on my side) it's true that task is already created when WF crashes, but if I opened it with IE and Developer Tools I've found no errors on it.

However, on my side I was looking for some clue on ULS logs, and I've found these relevant traces (I opened a new Nintex case from my side also, trying to figure out what's happening):

Unexpected        Error in MultiOutcomeTaskAndEscalation.: System.UnauthorizedAccessException: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))    

at Microsoft.SharePoint.SPGlobal.HandleUnauthorizedAccessException(UnauthorizedAccessException ex)    

at Microsoft.SharePoint.Library.SPRequest.GetListsWithCallback(String bstrUrl, Guid foreignWebId, String bstrListInternalName, Int32 dwBaseType, Int32 dwBaseTypeAlt, Int32 dwServerTemplate, UInt32 dwGetListFlags, UInt32 dwListFilterFlags, Boolean bPrefetchMetaData, Boolean bSecurityTrimmed, Boolean bGetSecurityData, Boolean bPrefetchRelatedFields, ISP2DSafeArrayWriter p2DWriter, Int32& plRecycleBinCount)    

at Microsoft.SharePoint.SPListCollection.EnsureListsData(Guid webId, String strListName)    

at Microsoft.SharePoint.SPListCollection.ItemByInternalName(String strInternalName, Boolean bThrowException)    

at Microsoft.SharePoint.SPListCollection.GetListById(Guid uniqueID, Boolean bThrowException)    

at Microsoft.SharePoint.Workflow.SPWorkflow.get_TaskList()    

at Ixw=.Fh0=.Gx0=(NWContextDataCollection HB0=, Approver HR0=, NWWorkflowContext Hh0=, ContextDataOptions Hx0=, Boolean IB0=)   

at Nintex.Workflow.HumanApproval.Message.Send(Approver approver, Message persistTo)    

at Nintex.Workflow.HumanApproval.Approver..ctor(NintexTask parentTask, String userID, String otherEmailAddress, Boolean allowDelegation, Message requestApproval, Message approvalNoLongerRequired, Boolean SendNotificationNow, Boolean IsDomainGroup, Boolean IsSPGroup, Int32 sharePointTaskId, ConfiguredOutcomeCollection outcomes, SPWorkflowTaskProperties taskProps)    

at Nintex.Workflow.Activities.MultiOutcomeTaskAndEscalation.CreateDBItems_ExecuteCode(Object sender, EventArgs e)    

at System.Workflow.ComponentModel.Activity.RaiseEvent(DependencyProperty dependencyEvent, Object sender, EventArgs e)    

at System.Workflow.Activities.CodeActivity.Execute(ActivityExecutionContext executionContext)    

at System.Workflow.ComponentModel.ActivityExecutor`1.Execute(T activity, ActivityExecutionContext executionContext)    

at System.Workflow.ComponentModel.ActivityExecutorOperation.Run(IWorkflowCoreRuntime workflowCoreRuntime)    

at System.Workflow.Runtime.Scheduler.Run()

[Forced due to logging gap, cached @ 12/20/2016 10:33:26.74, Original Level: Verbose] SQL connection time: 0.02668566138359 for Data Source=AP_SQL_SharePoint2013_PROD;Initial Catalog=WSS_Content_Workflows;Integrated Security=True;Persist Security Info=False;Enlist=False;Pooling=True;Min Pool Size=0;Max Pool Size=100;Asynchronous Processing=False;Connection Reset=True;MultipleActiveResultSets=False;Replication=False;Connect                ;Encrypt=False;TrustServerCertificate=False;Load Balance Timeout=0;Packet Size=8000;Type System Version=Latest;Application Name=".Net SqlClient Data Provider";User Instance=False;Context Connection=False;Transaction Binding="Implicit Unbind";ApplicationIntent=ReadWrite;MultiSubnetFailover=False;ConnectRetryCount=1;ConnectRetryInterval=10               0edcc29d-e3c9-70e2-ac77-fba935ef7368

12/20/2016 10:33:26.76               w3wp.exe (0x2784)                       0x3704  SharePoint Foundation                        Database                           8acb      High       [Forced due to logging gap, Original Level: VerboseEx] Reverting to process identity               0edcc29d-e3c9-70e2-ac77-fba935ef7368

12/20/2016 10:33:26.76               w3wp.exe (0x2784)                       0x1314  SharePoint Foundation                        Micro Trace                      uls4        Medium               Micro Trace Tags: (none)               0cdcc29d-b337-70e2-ac77-f45ef045b8f8

12/20/2016 10:33:26.76               w3wp.exe (0x2784)                        0x2388  SharePoint Foundation                        Micro Trace                      uls4        Medium               Micro Trace Tags: (none)               0edcc29d-93d6-70e2-ac77-f9eb5cb9b4b2

12/20/2016 10:33:26.77               w3wp.exe (0x2784)                       0x3704  Web Content Management                    Publishing                          7fz3       Medium               Setting [Display] as the FormContext.FormMode for the current page     0edcc29d-e3c9-70e2-ac77-fba935ef7368

12/20/2016 10:33:26.77               w3wp.exe (0x2784)                       0x3704  Web Content Management                    Publishing                          7fz3       Medium               Setting [Display] as the FormContext.FormMode for the current page     0edcc29d-e3c9-70e2-ac77-fba935ef7368

12/20/2016 10:33:26.77               w3wp.exe (0x2784)                       0x3928  SharePoint Foundation                        Micro Trace                      uls4        Medium               Micro Trace Tags: (none)             

12/20/2016 10:33:26.79               w3wp.exe (0x2784)                       0x10D0 SharePoint Foundation                        Micro Trace                      uls4        Medium               Micro Trace Tags: (none)             

12/20/2016 10:33:26.79               w3wp.exe (0x2784)                       0x3704  Metalogix Content Matrix                  Interactive                         1             Unexpected        Error occur while checking user is member of Organizer Ribbon Users group or user having full control over site collection. Detail:Impossible de trouver le niveau d'autorisation.    0edcc29d-e3c9-70e2-ac77-fba935ef7368

12/20/2016 10:33:26.79               w3wp.exe (0x2784)                       0x3704  Metalogix Content Matrix                  Interactive                         00000    Critical  Error occur while checking user is member of Organizer Ribbon Users group or user having full control over site collection. Detail:Impossible de trouver le niveau d'autorisation.    0edcc29d-e3c9-70e2-ac77-fba935ef7368

12/20/2016 10:33:26.79               w3wp.exe (0x1E98)                        0x33F4  SharePoint Foundation                        Micro Trace                      uls4        Medium               Micro Trace Tags: (none)               0edcc29d-93d6-70e2-ac77-fb77cc1d6f80

12/20/2016 10:33:26.80               w3wp.exe (0x2784)                       0x1E94  SharePoint Foundation                        Micro Trace                      uls4        Medium               Micro Trace Tags: (none)               0edcc29d-93d6-70e2-ac77-fb77cc1d6f80

12/20/2016 10:33:26.83               w3wp.exe (0x2784)                       0x3704  SharePoint Foundation                        Database                           ahjqp     High       [Forced due to logging gap, cached @ 12/20/2016 10:33:26.79, Original Level: Verbose] SQL connection time: 0.0307911477502961 for Data Source=AP_SQL_SharePoint2013_PROD;Initial Catalog=WSS_Content_Workflows;Integrated Security=True;Persist Security Info=False;Enlist=False;Pooling=True;Min Pool Size=0;Max Pool Size=100;Asynchronous Processing=False;Connection Reset=True;MultipleActiveResultSets=False;Replication=False;Connect Timeout=15;Encrypt=False;TrustServerCertificate=False;Load Balance Timeout=0;Packet Size=8000;Type System Version=Latest;Application Name=".Net SqlClient Data Provider";User Instance=False;Context Connection=False;Transaction Binding="Implicit Unbind";ApplicationIntent=ReadWrite;MultiSubnetFailover=False;ConnectRetryCount=1;ConnectRetryInterval=10               0edcc29d-e3c9-70e2-ac77-fba935ef7368

12/20/2016 10:33:26.83               w3wp.exe (0x2784)                       0x3704  SharePoint Foundation                        Database                           8acb      High       [Forced due to logging gap, Original Level: VerboseEx] Reverting to process identity               0edcc29d-e3c9-70e2-ac77-fba935ef7368

12/20/2016 10:33:26.83               w3wp.exe (0x2784)                       0x24D8 Nintex Workflow 2013                         General                              00000    Unexpected        (https://(SiteURL)_layouts/15/NintexWorkflow/preview.aspx?ListId=6f777efa-ff0f-49f9-b661-49df12f7f311...): Nintex.Workflow.NWActionExecutionException: La tâche comporte une erreur. ---> System.NullReferenceException: Object reference not set to an instance of an object.     at Ixw=.Fh0=.Gx0=(NWContextDataCollection HB0=, Approver HR0=, NWWorkflowContext Hh0=, ContextDataOptions Hx0=, Boolean IB0=)     at Nintex.Workflow.HumanApproval.Message.Send(Approver approver, Message persistTo)     at Nintex.Workflow.HumanApproval.MultiOutcomeTask.ClosePendingApprovers(Boolean informPendingApprovers, Outcome reason, UpdateApproverTaskMode closureMethod)     at Nintex.Workflow.Activities.MultiOutcomeInternal.TaskCompleted(Object sender, EventArgs e)     at System.Workflow.ComponentModel.Activity.RaiseEvent(DependencyProperty dependencyEvent, Object sender, EventArgs e)     at System.Workflow.Activities.ReplicatorActivity.Cancel(ActivityExecutionContext executionContext)     at System.Workflow.ComponentModel.CompositeActivity.HandleFault(ActivityExecutionContext executionContext, Exception exception)     at System.Workflow.ComponentModel.ActivityExecutor`1.HandleFault(T activity, ActivityExecutionContext executionContext, Exception exception)     at System.Workflow.ComponentModel.ActivityExecutorOperation.Run(IWorkflowCoreRuntime workflowCoreRuntime)     at System.Workflow.Runtime.Scheduler.Run()     --- End of inner exception stack trace --- (Build:3190)       0cdcc29d-334b-70e2-ac77-fefc49e896aa

12/20/2016 10:33:26.83               w3wp.exe (0x2784)                       0x24D8 Nintex Workflow 2013                         Activity Execution                           00000    Unexpected        Error in CancellingParallelActivity.: System.NullReferenceException: Object reference not set to an instance of an object.     at Ixw=.Fh0=.Gx0=(NWContextDataCollection HB0=, Approver HR0=, NWWorkflowContext Hh0=, ContextDataOptions Hx0=, Boolean IB0=)     at Nintex.Workflow.HumanApproval.Message.Send(Approver approver, Message persistTo)     at Nintex.Workflow.HumanApproval.MultiOutcomeTask.ClosePendingApprovers(Boolean informPendingApprovers, Outcome reason, UpdateApproverTaskMode closureMethod)     at Nintex.Workflow.Activities.MultiOutcomeInternal.TaskCompleted(Object sender, EventArgs e)     at System.Workflow.ComponentModel.Activity.RaiseEvent(DependencyProperty dependencyEvent, Object sender, EventArgs e)     at System.Workflow.Activities.ReplicatorActivity.Cancel(ActivityExecutionC...           0cdcc29d-334b-70e2-ac77-fefc49e896aa

12/20/2016 10:33:26.83*             w3wp.exe (0x2784)                        0x24D8 Nintex Workflow 2013                         Activity Execution

[jacobarn · Accepted solution]

So I found out what our problem was. when a user submits a form SharePoint uses that same user login to create the task list item. However, I did not have Contribute rights for those users that submit forms on the Workflow task list which is what caused the error.

Even if you create unique permissions on the flexi task item in the workflow that doesn't give them permission to create the Workflow Task item.

[cassymfreeman]

so you resolved this issue ‌?  Can you mark the answer as correct in this thread so that other users can see the solution.

Thanks
Cassy