I have a basic mouse connected to my computer running Ubuntu 18.04 via USB (it is a wired mouse). All of a sudden my mouse scrolling wheel stopped working. This is odd since it was working before, and I can confirm it is not a mouse hardware issue since the mouse wheel works fine on other computers.
I've tried unplugging and plugging the mouse back in, restarting my computer, getting all the latest updates with no luck. I tried toggling natural scrolling in the settings as others have suggested.
Also, I ran xev and the application did not pick up any activity when I used the middle scroll button. I am stumped and have no idea what else to try, it doesn't seem like many other people have had this problem there wasn't much troubleshooting available online.