Shadows get cut off and pixelated

Hi all!

I have a problem with the shadows of Unity and ARKit working together. Namely, the shadows are shown pixelated from a certain model size. I've already looked in the shadows options in the quality settings and adjusted the shadow options from my directonal light. When I run the app on the ipad, the shadows are get cut off on the side of the display. The whole model have size of 42 x 30cm. Can someone help me with these two problems? I've attached images of my settings and the problem itself where its occurs. thanks in advance.

 

i am sorry for the double post but does nobody knows how to fix this?