Error 0x800721BB

Value: -2147016261 | 0x800721BB | 2147951035

What does it mean ?

ERROR_DS_FLAT_NAME_EXISTS_IN_FOREST  
The flat name of the trusted domain already exists in the forest.
Value: 8635 | 0x21BB | 0b0010000110111011

Where does it come from ?

FACILITY_WIN32  
Provides a way to handle error codes from functions in the Win32 API as an HRESULT. (Error codes in 16 - bit OLE that duplicated Win32 error codes have also been changed to FACILITY_WIN32)
Value: 7 | 0x007 | 0b00000111

Other Errors for FACILITY_WIN32