Question Two questions i need answered please Unity friends.

First question, I have made my first AR app which tracks planes and spawns selected object on to it.
Everything works fine... Until i add a canvas(Screen space Overlay) with buttons on it.

At this point my Plane Tracking stops working entirely. Any ideas as to why that might be the case?

Second question, I have created a prefab out of several models but the pivot point is in the center of the object?
I added an empty game object and put the pivot at the bottom and then threw the prefab into it expecting the pivot of the parent object to become my main pivot.
This didn't work and the pivot is still in the center.. Any Ideas as to what could be causing both these issues would be a great help.

If you need screenshots of anything let me know.

 

Question 1: Before i added the Canvas and Buttons the plane tracking would appear on walls and floors and surfaces.
After i added the Canvas and Buttons the Plane Tracking doesn't show up in the test build but a previous iteration of my project with no canvas or buttons works perfectly.(I'm too inexperienced to tell you anything other than what I have said for Q1)

Question 2: You solved this issue for me, Thanks.

 

Help on the first issue when possible please.

 

Redoing the tutorial now, Will ask my mentors when i see them. Thanks!