S4u Slice license problems with SketchUp 2020

I bought the Sketchup 2019 version of s4u Slice. When installing on sketchup 2020 I get the message “No license fo product (-1)”;.
I have already asked to the develloper in their own site and I was told that:

“S4u slice works on Sketchup 2020.
Maybe you install it on more 2 computers.
You need uninstall it on your old Sketchup.
Or you contact to Sketchup team for reset your license.”

I have already uninstalled the plugin in the second computer, but the problem persists.

Does anybody have any idea about what to do?

I’m not sure why the uninstall didn’t free up that activation. I will fix things for now, but if you frequently changes computers remember to remove SketchUp licenses and remove paid for extensions.