Error 0x8051002B

Value: -2142175189 | 0x8051002B | 2152792107

What does it mean ?

OPC_E_DS_INVALID_SIGNATURE_COUNT  
A Signature part does not contain the signature markup for exactly one signature.
Value: 43 | 0x002B | 0b0000000000101011

Where does it come from ?

FACILITY_OPC  
Open Connectivity Service (Package Consumption)
Value: 81 | 0x051 | 0b01010001

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