I have a Sketchup Pro 2018 license, and have installed it on my desktop and my laptop, correct license information entered in both computers. The laptop mistakenly got Sketchup 2019 installed (Sketchup 2018 disappeared), which of course I don’t have a license for and was unable to use. I uninstalled SU 2019, installed SU 2018 and entered my license information. Now I’m getting emails from SU saying that I have exceeded the number of computers I’m allowed to install the license on.
Why did SketchUp 2018 disappear? Installing SketchUp 2019 doesn’t overwrite 2018. Each major version of SketchUp installs as a separate program.
If your Maintenance and Support was up to date, you should have a license for SU2019.
You should probably contact Customer Support directly so they can free up the license.