Complete the steps in the order listed below until the issue is resolved:
  1. Select WebPurchasing virtual directory in IIS, then select Authentication and ensure that Windows Authentication and ASP.NET Impersonation are enabled
  2. Select WebService virtual directory in IIS, then select Authentication and ensure that Anonymous Authentication is enabled
  3. Remove the WebPurchasing and WebService virtual directories in IIS and configure them again using the WebPortal Configuration Tool
  4. Uninstall WebPortal, remove the WebPurchasing and WebService virtual directories in IIS, remove the FEOnline application pool in IIS and re-install WebPurchasing.  NOTE:  Before uninstalling WebPurchasing, make note of any settings in the WebPortal Configuration Tool that will be needed to re-configure WebPurchasing once re-installed.