Error 0x80310031

Value: -2144272335 | 0x80310031 | 2150694961

What does it mean ?

FVE_E_PROTECTOR_EXISTS  
This key protector cannot be added. Only one key protector of this type is allowed for this drive.
Value: 49 | 0x0031 | 0b0000000000110001

Where does it come from ?

FACILITY_FVE  
Full volume encryption
Value: 49 | 0x031 | 0b00110001

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