Issues with exporting rigs and animations

Hello, I’m working on making custom characters for a game and I’m having some problems while exporting rigs from blender to studio. I made a vary basic one just to test: here’s how it looks like

I exported it as an FBX file and imported it to studio with the avatar importer plugin. When i open the animation editor and import the animation, some bones aren’t in the correct place, only some are:

Some bones don’t show up as purple in studio either. I’ve tried following tutorials but they all lead me to this. Are there any solutions?

This is happening with me too I am trying to import S15 Avatars