We are using Sharepoint 2016. Everything for the Nintex workflow was working as expected.
Then, the workflow tasks (few of them) are not opening and giving error as 'Something Went wrong' when user tries to Approve.
Also, the Nintex workflow history page shows no instance of running workflow(/_layouts/15/NintexWorkflow/ItemWorkflows.aspx?ListId={fe28238d-wer-471c-95bb-a1645e93ba69}&ItemId=4112).
The log from Nintex says the below.
at Nintex.Workflow.HumanApproval.NintexTask.eR8=(SPWeb eh8=, Guid ex8=, Int32 fB8=)
at Nintex.Workflow.HumanApproval.NintexTask.RetrieveTask(Int32 spTaskID, SPWeb web, SPList taskList)
at Nintex.Workflow.ApplicationPages.ApproveReject.Page_Load(Object sender, EventArgs e)
at System.EventHandler.Invoke(Object sender, EventArgs e)
at System.Web.UI.Control.OnLoad(EventArgs e)
at Microsoft.SharePoint.WebControls.UnsecuredLayoutsPageBase.OnLoad(EventArgs e)
at Microsoft.SharePoint.WebControls.LayoutsPageBase.OnLoad(EventArgs e)
at Nintex.Workflow.ServerControls.NintexLayoutsBase.OnLoad(EventArgs e)
at System.Web.UI.Control.LoadRecursive()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)