X axis mirror not working

i’m trying to edit a mixamo aramature and i select x-axis mirror but it does work for some reason. anyone know why? thx

I think you have rename the bones, how to do that with all the bones autmatically I don’t know.

https://docs.blender.org/manual/en/latest/animation/armatures/bones/editing/naming.html#naming

edit: to speed up the process I press f2 on the keyboard to bring up the name to edit on the bones.