Item had unknown error

in a Cimplicity project, I have two devices, both connected to PLC using an OPC server.
In the logging of Cimplicity, I see a few times a day some errors:

23/12/2015 0:54:56 Failure 5548 OPC_0 COPCCallback::OnDataChange -2147352566
Item had unknown error
Error of type: COR_DCRP_ERR, Code: 20016

23/12/2015 0:54:48 Failure 5548 OPC_0 COPCCallback::OnDataChange -2147352566
Item had unknown error
Error of type: COR_DCRP_ERR, Code: 20016

22/12/2015 10:48:01 Failure 5548 OPC_0 COPCCallback::OnDataChange -2147352566
Item had unknown error
Error of type: COR_DCRP_ERR, Code: 20016

22/12/2015 10:08:39 Failure 5548 OPC_0 COPCCallback::OnDataChange -2147352566
Item had unknown error
Error of type: COR_DCRP_ERR, Code: 20016

22/12/2015 9:58:24 Failure 5548 OPC_0 COPCCallback::OnDataChange -2147352566
Item had unknown error
Error of type: COR_DCRP_ERR, Code: 20016

22/12/2015 9:57:19 Failure 5548 OPC_0 COPCCallback::OnDataChange -2147352566
Item had unknown error
Error of type: COR_DCRP_ERR, Code: 20016

21/12/2015 10:46:20 Failure 5548 OPC_0 COPCCallback::OnDataChange -2147352566
Item had unknown error
Error of type: COR_DCRP_ERR, Code: 20016

Does anybody have any idea what is the cause of this error and how to solve this?