Authentication failed

<?xml version="1.0" encoding="UTF-8"?>    
<response>    
 <errors type="array">   
 <error>Authentication was failed</error>    
 </errors>    
</response>

If you get this message, it means that our system can't find your account according to the received data.
Please check that you set 'Authorization: Basic ' key with Base64 pair of Shop ID and Shop Password in HTTP header.

To get ShopID an Shop Password please log into the backoffice system (https://secure.psbill.com:8443/login) and select Shop Settings tab.