401 when calling UpdateCustomer action

[spielinger]

Hi!

I have successfully installed the API plugin. The sample application (nopCommerce-Api-SampleApplication) works fine with "GetCustomers". I also added a "GetProducts", which also worked like expected. But the sample action "UpdateCustomer" ends with an error message:
System.Net.WebException: 'Der Remoteserver hat einen Fehler zurückgegeben: (401) Nicht autorisiert
/ (401) not authorized

Any hint would help!

Thanks
Carsten