Run animation from Unity Asset store pack not playing correctly for custom model

I recently downloaded an animation pack from the Unity Asset store called Fighting Unity Chan. I am trying to retarget one of the run animations in it to my custom model and it looks...well it does not look correct. I've made sure that the avatar for my model (which I got from Mixamo) is humanoid and so is the one for the running animation, but that did not solve the problem. Here is what it looks like (the first model is my custom one and the second one is the original one that the animation came with):

Here are the settings for the animation:









This is the T pose for the model that came with the animation, i.e. the one from which the avatar for the animation is copied:



And this is the T pose for my custom model:



And finally, here are the properties of the animation in the Animator window:





What could be the problem here and how can I fix this animation?

 

Sorry for the shameless bump. Anybody know why the problem above might be happening?