SketchUp discontinued the sale of new "Classic" perpetual licenses in late 2020.
A 2020 license key will only work for the 2020 version of the software; it cannot "upgrade" to 2021 or newer without a subscription.
to the official SketchUp License look-up tool.
If you are searching for a "SketchUp Pro 2020 classic license key and authorization number 2021" via third-party "crack" sites or key generators, be aware of the significant risks:
Remove from Old Devices: SketchUp Pro classic licenses typically allow for two installations (e.g., a desktop and a laptop). If you are moving to a new machine, open SketchUp on the old one, go to Help > License, and click "Remove License."
