Custom light shader not lighting up on iOS devices

Hi!
I wrote a toon shader following your excellent toturial, it was supposed to receive point light according to the light position. it was working fine on standalone build, but when I tried to build a iOS version, I found out that the shader is not recieving light at all. When I switched the shader from custom light to emissive, and change point light to directional light. In the iOS build, the shader is recieving light again.