Error 0x800721B7

Value: -2147016265 | 0x800721B7 | 2147951031

What does it mean ?

ERROR_DS_RESERVED_MAPI_ID  
Schema update failed: The MAPI identifier is reserved.
Value: 8631 | 0x21B7 | 0b0010000110110111

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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