Creation of Outlook Calendar Appointment using Nintex Workflow in Sharepoint 2010 (Workflow Error - Failed to invoke Microsoft Exchange web service. The request failed with HTTP status 401: Unauthorized.)

Hi,

We are currently working on a project to allow supervisors to create appointments in the Outlook Calendar of their Team members in Sharepoint 2010 through Nintex Workflows. (http://blogs.perficient.com/microsoft/2011/03/how-to-create-an-outlook-appointment-using-nintex-workflow-2010/).

However we are currently faced with a workflow error: Workflow Error - Failed to invoke Microsoft Exchange web service. The request failed with HTTP status 401: Unauthorized.

We don't know what causes this error. The user account that will be creating appointments on another user's calendar can access the exchange web service via browser with no errors.

We don't know what we are missing (IIS authentication settings for Exchange Web Service or Sharepoint?).

Has anyone encountered the same error when using Nintex Workflow?

Please help. Thank you very much.

Ron