Maybe this can help: Error "Unauthorized attempt to update approval task by DOMAINUsername" in LazyApproval Email | Community (nintex.com)

@bamaeric We are not using Lazy Approval, so those services are not needed.

This is the ULS log

 (https://ext………./_layouts/15/NintexWorkflow/preview.aspx?ListId=cf90d929-3315-466e-96cd-f0c376968179&ItemId=9696&InstanceId=a3faf11b-02e0-469e-9999-67ecb1191f68): Nintex.Workflow.NWActionExecutionException: Error in request data action. ---> Nintex.Workflow.NWHumanApprovalException: Unauthorized attempt to update collect data task by i:0#.w|xyz\yz.xyza,xyz.zyza@xyz.co.uk. The response has not been recorded.    
 at Nintex.Workflow.HumanApproval.CollectDataFromUserTask.ProcessResponse(User user, String comment, Outcome outcome, Int32 taskListItemId, Boolean forEscalation)    
 at Nintex.Workflow.Activities.CollectDataTaskAndEscalation.AfterOnTaskChanged(Object sender, ExternalDataEventArgs e)    
 at System.Workflow.ComponentModel.Activity.RaiseGenericEventaT](DependencyProperty dependencyEvent, Object sender, T e)    
 at System.Workflow.Activities.HandleExternalEventActivity.RaiseEvent(Objecty] args)    
 at System.Workflow.Activities.HandleExternalEventActivity.System.Workflow.ComponentModel.IActivityEventListener<System.Workflow.ComponentModel.QueueEventArgs>.OnEvent(Object sender, QueueEventArgs e)    
 at System.Workflow.ComponentModel.ActivityExecutorDelegateInfo`1.ActivityExecutorDelegateOperation.Run(IWorkflowCoreRuntime workflowCoreRuntime)    
 at System.Workflow.Runtime.Scheduler.Run()     -
 -- End of inner exception stack trace --- (Build:3130)

Hi @SadanandKier ,

Looking at the workflow history it is possible that that the error that occurred prior to the task error may be the real issue here. This will need in depth analysis so I suggest contacting Nintex support in this instance.