Usually this means the ball part is stuck and/or the ink surrounding it has dried out.

Here’s a close up of how they work: https://youtube.com/shorts/7KGqGAlxwJs

If no ink gets transfered unto the ball, it’s not able to write anything.

The ink gets all stiff and gunky and doesn’t transfer to the ball. The ball might not even spin at that point. Lick it.

I know that you can use a cigarette lighter, very briefly, to burn off the stuck-on ink off the ball… otherwise the ball will pop out because the ink behind it turns to steam, I assume.

I believe there’s a chemical (maybe isopropyl alcohol?) That you can apply to the ball to dissolve the ink as well.

By design by Big Pen

Pens can often pick up paper fibers that gum up the works. In the case of ballpoints I can see this being a pretty permanent problem once it builds up enough to stop up the pen

The ink can dry out or some contaminant can get on the ball and preventing it from rolling. What I usually do is run the ball along the sole of my shoe (or use anything that has high friction material) 9 times out of 10 it makes the pen work again.

Why can my car stop running forever when there’s still a full tank of gas?