Moon animator animation not playing

Hello, everyone. I’ve been trying to make a simple fps game. I’m using a viewmodel with a left arm, right arm, humanoid root part, and gun that are all mesh parts. I’m able to see my hands just fine, but I can’t animate them so that they appear to be holding the gun.
The animation is looped and there is one keyframe: the position that I want my hands to be in as they are holding the gun.

I’m exporting my animation, publishing it as a keyframe sequence to roblox, then playing it in a script. The animation just isn’t playing, but everything else works fine.

I’ve tried using roblox’s animation editor but that had no luck, either.

Also, whenever I try to reopen my animation in Moon Animator, my animation disappears, which I thought was very odd. I need to create a whole different viewmodel (which is identical to the original one) to animate again.
Does anyone know what I can do to fix this problem? Thanks!

What I have (the piece on top is the handle of the gun):

What I want:

I’m following this tutorial: Designing an FPS Framework: Beginner's guide

Update: The animation works!! I restarted everything and now it all runs fine. I didn’t purposely change anything and followed the same steps, but Moon Animator was giving me less trouble, so there may have been a small problem with the rig.