Error 0x803D0018

Value: -2143485928 | 0x803D0018 | 2151481368

What does it mean ?

WS_E_PROXY_REQUIRES_BASIC_AUTH  
The HTTP proxy server requires HTTP authentication scheme 'basic'.
Value: 24 | 0x0018 | 0b0000000000011000

Where does it come from ?

FACILITY_WEBSERVICES  
Web Services
Value: 61 | 0x03D | 0b00111101

Other Errors for FACILITY_WEBSERVICES