Apple - Three-finger trackpad gesture on Mission Control and Expose not working in my Mac Pro

This sometimes happens to me, where the 3-finger macro stops working. Seems like OSX just bugs out. My hotfix right now is to open the command line and run killall Dock. Seems to work fine for resetting it and getting it working again.

I had the same issue on macOS Catalina (and I had it on macOS Mojave as well. The problem with Mission Control was the reason I upgraded), but it turns out it was Mission Control that not worked (would not open using keyboard either). This solved it for me;

1. Open a command line shell in Terminal application (search for Terminal in Spotlight if you're not familiar)

2. Copy and paste the following command:

   defaults write com.apple.dock mcx-expose-disabled -bool FALSE

3. Copy and paste the following command (restart the OSX Dock):

   killall Dock