Cause
The user-defined property '<x>' to be imported at the PLC card with the device identification '<y>' is unknown since the parts data for the PLC card in the parts management is not up-to-date.
Solutions
Possibility 1
- Ask the manufacturer whether an updated part with the reported property is available.
- If yes, import the part and assign it to the PLC card.
Possibility 2
- In the parts management add the missing user-defined property at the part.
- Then assign the part to the PLC card.
- Import the PLC data again.