Error 0x8004231A

Value: -2147212518 | 0x8004231A | 2147754778

What does it mean ?

VSS_E_WRITER_ALREADY_SUBSCRIBED  
The writer has already successfully called the Subscribe function. It cannot call Subscribe multiple times.
Value: 8986 | 0x231A | 0b0010001100011010

Where does it come from ?

FACILITY_ITF  
COM/OLE Interface management. FACILITY_ITF is designated for user-defined error codes returned from interface methods
Value: 4 | 0x004 | 0b00000100

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