I am trying to Download Additional Content Files (License required), but each time I enter my serial number I get

Invalid license entry!

I hope this is just a glitch and not an omen of upgrading issues to come.

The supreme irony of life is that hardly anyone gets out of it alive.
Robert A. Heinlein

11th Gen Intel(R) Core(TM) i9-11900K @ 3.50GHz   3.50 GHz
64.0 GB (63.9 GB usable)
Geforce RTX 3060 12 GB
Windows 11 Pro