My Avatar Body disappears after I put an outfit on

My avatar body disappears. how do I fix it? Only on this outfit. I am really new to unity so an in-depth explanation would be really appreciated!

Can you provide a source of where you got the outfit?

Usually it is because animations will update “blendshapes” to shrink your body when the outfit is on to avoid clipping.
You can see them on the body object in unity

How can I find which animation is shrinking the shape? Do I need to go through them manually? I bought the outfit from booth. It’s the latest model

You would need yeah, if you don’t have any knowledge in Unity it’s going to be hard. The easiest would be to contact the asset creator and ask them directly through their message or support page.