Animations Stopped Working?

So, this is a total dumb noob situation…

I was trying to import one of those Mixamo meshes into a 3rd Person template I have been using. I figured I could retarget the animations to the unreal skeleton, so I chose that skeleton to be its skeleton in the import dialogue. I get a “failed to merge bones” error. Then… I forget what I did. I think I chose to not regenerate skeleton from mesh? But when I opened the mesh I couldn’t see anything so I closed it, reopened, then said yes to regenerate skeleton, not really knowing what that even means.

Anyhow, it wasn’t animating. I decided to delete the things I had imported and just start over. That’s when I noticed that my original mesh now wouldn’t play any animations. Its head seems to move corresponding to the animations, but the rest is t pose.

So, I don’t know what I did wrong and don’t know how to fix it, but I would really like to fix it!
Is this enough information? Does anybody know how I messed up?