Unrecognized activity encountered

Hello everyone,

I’m working with Nintex workflow for Sharepoint 2016.

I have a workflow with three custom actions. When I execute the workflow I have the following error:

Unrecognized activity encountered: NextApprover.NextApproverActivity

More details below.

I have a workflow with three custom actions. One of this custom action has the name NextApprover.

During the execution of the flow this happens (all action run as workflow owner)

1. The Workflow executes some operation on SharePoint list
2. For each
   1. Iteration 1
   2. It executes the custom action NextApprover => is successful
   3. The Workflow executes some operation on SharePoint list and it executes flexy task
   4. Iteration 2
   5. It executes the custom action NextApprover => is not successful and crashes with the following error message: Unexpected       System.InvalidOperationException: Unrecognized activity encountered: NextApprover.NextApproverActivity.     at Nintex.Workflow.Activities.ProgressTrackingActivity.LogProgress(Boolean actionComplete, NWWorkflowContext ctx, ActivityFlags flags)     at Nintex.Workflow.Activities.ProgressTrackingActivity.LogProgressStart(NWWorkflowContext ctx)     at NextApprover.NextApproverActivity.Execute(ActivityExecutionContext executionContext)     at System.Workflow.ComponentModel.ActivityExecutorOperation.Run(IWorkflowCoreRuntime workflowCoreRuntime)     at System.Workflow.Runtime.Scheduler.Run()

I made a change to the workflow by adding the custom action within the approve branch of a flexy task, in this case the custom action always works, for each iterations.

Unfortunately, this solution does not meet expectations.

Why does the custom action work in flexy task action and doesn’t outside?

Same thing happens for another custom action: ProtocolModule.

During the workflow execution I get the error in the logs: Unrecognized activity encountered: ProtocolModule.ProtocolModuleActivity.

I tried to uninstall and install wsp, but it doesn't solve the problem.

Thanks for the help!

Lili