Vector pass doesn't work with moving objects?

I tried to add motion blur to a particles in post processing, so I enabled vector pass, baked particles (which are moving really fast) and got blank vector pass. After a couple of more tries I decided to test the pass in a blank project with a simple cube and got the same result, but when I tried to rotate the cube vector pass worked. Is there another way to add motion blur to particles? Because I can’t really move them without breaking cache

The Vector pass can have trouble with very fast-moving particles. It’s hard to tell how fast something is moving if it doesn’t exist on the frame before and the frame after. Try the Cycles built-in motion blur instead (you can enable it in the render settings)