Autodesk ended automatic reauthorizing of 2010 and older software as of August 31 2019, read all about it here https://knowledge.autodesk.com/support/autocad/learn-explore/caas/simplecontent/content/previous-ver... Sorry, you missed the deadline.
If you still have your old Win7 PC and all works well, hang on to it for as long as it will last, then figure out a new option if you are unable to join Autodesk Subscription for newer software. If you find Autodesk software subscriptions too expensive, there are many other CAD packages out there with no subscription options (initial cost may still be comparably high) that you can go get and use.
