'Create Neighbor Terrains' Not Working Properly!

I’m using Unity 2019.1.0a14 and when I try to make a neighbor terrain it doesn’t connect like it is supposed to. Also, I’m having issues with the ‘Terrain Tools’ package.

What do you mean by they don’t connect?
I’m having null on top, bottom, left and right terrains by code.

https://forum.unity.com/threads/neighbour-terrains-always-null-on-execution.823275/