Error 0x8004004C

Value: -2147221428 | 0x8004004C | 2147745868

What does it mean ?

TAPI_E_CALLCENTER_INVALAGENTACTIVITY  
Invalid agent activity.
Value: 76 | 0x004C | 0b0000000001001100

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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