@tig said:

Install the latest versions of the extension, and LibFredo, and the SketchUcation toolset [which deals with SCF licensing].
Restart SketchUp afterwards to sync everything.

If you don't have a license you must buy one... then activate it...

There are several posts about this on the forum...

I'm having the same issue.

I just downloaded Sketchup 23.1.340, and I have installed:
Curviloft 1.9b
LibFredo6 14.2a
SketchUcation Toolset 4.3.1
(as far as I can tell, the latest versions of everything)

When I attempt to use Curviloft, I get a message that my free license expired on Thursday 30th December 2021

I have tried restarting both SketchUp and my computer, but nothing is working...

Any idea what to try next?