Error 0x801901F5

Value: -2145844747 | 0x801901F5 | 2149122549

What does it mean ?

HTTP_E_STATUS_NOT_SUPPORTED  
Not implemented (501).
Value: 501 | 0x01F5 | 0b0000000111110101

Where does it come from ?

FACILITY_HTTP  
HTTP support
Value: 25 | 0x019 | 0b00011001

Other Errors for FACILITY_HTTP