Shadow won't work on object that is close to ground.

The shadow won’t show if the object is too close to the ground for some reason, if I pull it up a bit it casts a shadow but as it gets closer to the ground the shadow disappears. I’m not sure why.

Reduce the bias.

Thanks really enhanced the look as it affected the shading of the ground too, neat. For those who have a similar problem, the sun/spotlight bias.