Mask not showing up?

I've made a mask on a new node to change the color of a particular spot in the image, however the adjustments are not visible in the viewer. The original image remains unchanged. I can see the adjustments are being made because as I slide the wheel around, I see the color changing in the node's thumbnail... just not in the viewer.

I am also able to see the adjustments when I toggle on the highlight, however then I only see the masked area and the rest of the image is grey. I would like to see my adjusments in the viewer in relation to the rest of the image, so this doesn't help.

Any idea what's wrong?

(I am using Da Vinci Resolve 16.1)

Make sure you don't have "Bypass Color Grades and Fusion Effects" enabled.

You've probably figured this out by now, but just in case......You might be playing back at half/quarter resolution? I just figured out that Fusion effects won't appear when you're in Proxy mode - Playback Menu>Proxy Mode. Hope that helps!