Error 0x800721C1

Value: -2147016255 | 0x800721C1 | 2147951041

What does it mean ?

ERROR_DS_HIGH_ADLDS_FFL  
The functional level of the AD LDS configuration set cannot be lowered to the requested value.
Value: 8641 | 0x21C1 | 0b0010000111000001

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

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