Then you need to determine what it is on your machine that changes that breaks the license. Maybe Windows Update, or Anti-Virus, or some other domain change. In any case, do some research and create a restore point to see if going back to a certain date when it was working will be a suitable solution for you.
The solution of my problem occurs to be much more simper. It turns out, that FLEXnet Licensing Service was turned off. I don’t know why it was turned off, but after turning it on Inventor starts without any problem. Thank you for the link with information about this service.