Error 0x803D001B

Value: -2143485925 | 0x803D001B | 2151481371

What does it mean ?

WS_E_PROXY_REQUIRES_NEGOTIATE_AUTH  
The HTTP proxy server requires HTTP authentication scheme 'negotiate'.
Value: 27 | 0x001B | 0b0000000000011011

Where does it come from ?

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

Other Errors for FACILITY_WEBSERVICES