Error 0x8004504F

Value: -2147200945 | 0x8004504F | 2147766351

What does it mean ?

SPERR_REMOTE_CALL_ON_WRONG_THREAD  
When making a remote call to the server, the call was made on the wrong thread.
Value: 20559 | 0x504F | 0b0101000001001111

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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