I think this thread applies to people who already have a registered Cubase version. In this case, the OP has an outdated code that dates back to the old licensing system. But who knows, maybe Matthias has an idea or can offer help.
I would also suggest to contact Steinberg support via email. But to be honest - I don’t know which way is best or most promising to proceed in this case.
Steinberg is usually really generous so give it a try @David_Baldwin .
Good luck !