Hi,

What user is being authenticated on the K2 Server?

It might be that the Identity impersonate="true" flag is not set for the web application and that the AppPool user account is opening the connection to the K2 Server but that this user does not have the task and therefore the error is raised. Check the K2 logs to determine which user is being authenticated and if it is the AppPool user account, verify that the identity impersonate="true" flag is set in the web application's web.config file.

If the correct user is being authenticated, ensure that you do not call the ProcessInstance.Update() before calling the execute method on the action. This method is not necessary as the action will save the values of the data fields when the action is executed. Both an Update action and a Finish action will save the data fields when executed. If you are calling the Update() method, remove that from the code and try again.

If it is still not working, post the code for the method which raises this exception here so that we can see what else might be causing this problem.

Regards,

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• Make sure that the person approving has rights to take action.Workspace > Management > Workflow Server > Processes > [Project Name] > [Process Name] > Process Rights. At least View Participate rights should be there.
  

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• Another instance in which this might happen is if user tries to complete the task which is not assigned to him or task already completed.
  

Good Luck.