@Svenne: It is not rare that the dongles slowly start malfunctioning, increasing the number of ‘No valid license found’ over time. The dongle you are currently using is almost 10 years old, so it could easily be.
Although it is recommended to update the eLCC, it is not a requirement, one might just use the same version until a new version of Cubase is installed and only update it in case of issues. Don’t think it’s your case, but sometimes USB sleep can trigger that message as well.