Kerning classes not working

In the screenshot below, I applied pair adjustment to two classes, but I’m not seeing the change applied.

I’ve done pair adjustments before using kerning classes in other fonts. What am I doing wrong? Thanks.

Latin Default is used by the shaping engine, and that lacks the kern feature. Add it there as well, and you are good to go!

Note: you can use the Proofing tool (second icon at the upper left toolbar) to see what is being applied.

Got it, thank you!