Cannot preview animations in the scene

Hi,

Please note I'm completely new to Unity so forgive me if this is extremely nooby or I'm not using the correct terms.

Previously when making animations in the Animation panel, if I would move the pointer in the timeline around, it would show the different stages of the animation (the model in the scene would move according to where I click on the timeline). That was how I was previewing my animations. But suddenly this doesn't work anymore; now the model just stays in the same position I last moved it, and moving the pointer in the timeline does nothing.

Why doesn't it work anymore, is there another way I'm supposed be doing this?

Thanks