I can't seem to use these skm files

https://www.jotun.com/th/th/b2b/colours/digital-colour-palette/
On this page, scroll down a bit and there will be a selection of sketchup materials pre-made with colors matching the paint catalogue. Almost all of them work properly except the “Global Trends 2021” zip file. The files extracted properly, but when I try to select materials they don’t appear for selection at all.

I’m currently using sketchup pro 2020. Is it possible that these skm files were made with a newer sketchup version and won’t work with my version? Any help appreciated.

SKM files are not version dependent.
I’ve tried that SKM set and nothing shows in SketchUp because the SKM files in the ZIP are somehow corrupt.
Contact the author of that file-set as something has gone wrong in their processing…
A SKM is a re-suffixed ZIP file but even if renamed it does not open.

Only the original author can fix this…

Thank you. I’ll try contacting the author.