A HTTP 401 error means that access is denied to the webservice URL. Make sure the correct IUSR is being used in the virtual directories of SightMax in IIS.
Open up IIS and navigate to the SightMaxWebServices virtual directory.
Right click on the directory > Properties > Security Tab > Click the Edit button on the Anonymouse Access and Authentication Control > Click Advanced > Click Find Now.
A list of users will appear. Select the correct IUSR on the machine, and click OK to close all dialogue boxes.