Can you please confirm that the animation clip you want to play is a legacy animation clip?
If you are unsure, please open up PlayAnimation.cs and add this line of code in the OnInit method: animationClip.value.legacy = true; so that the OnInit looks like this in the end:
By the way, the animationclip is added automaticaly for you if it’s not in the animation clips list of the Animation component, so that you don’t have to add it manualy.