Axes Location problem (Optical Size)

Hi, I try to create a variable font using the optical size variable but when I try it doesn’t work.
I insert the Optical Size Axes in: Font info > Font and in: Font info > Master I use the custom parameter to insert the optical size value.

You Glyphs is very old. You should update to the latest version. Any reason you didn’t do that yet?

Yes, it is probably the problem. I’ll do that right now.