License is not valid - error 4351

[ime]

We are using novaPDF Lite Version 8.9 Build 950 for many years on many devices worldwide. On one device we received the following error message: "License is not valid for printer Diagnosis PDF Printer (error 4351). Print job will be canceled"

The printer name is correct. Can you please let me know what causes 4351? I could not find any details on this specific code.
Also, how can we fix the issue?

Kind regards!