Check for any EventSystems in your scene that aren’t part of the CursorControl prefab. Your EventSystem is most likely being overwritten by another EventSystem component.
Some version of Unity, like 2019, have different rules for UI Handlers. Add a Button component to your image and use the “OnClick” event attached instead.
On the CursorControl game object, make sure you have both the Render Camera variable on the canvas component and the Camera Main variable on the CursorController component assigned to the same camera.