I cant put a chest on llamas/donkeys/mules. Please help?

I cannot put a chest on llamas/donkeys or mules.

 

Whenever I try to put a chest on one of these animals it does not work. It will either put me on the animal or it will put the chest on the ground.

I have tried in many variations to put the chest on llamas/mules/donkeys but nothing seems to work.

I went to the older version of minecraft on the xbox one and had no trouble with it but I still cannot do it on the Better Together version.