Repositionning a BodyBack accesory doesn't work

Ik it’s not really scripting but…
I put a BodyBack attachement to my Bullet Proof vest so it move depending on the torso, and not of the head (cuz it make it enter INSIDE the player, which is odd…), so I ut a BodyBackAttachement to the Handle part, and then… Nothing.
I can’t reposition it since I add this thing. Why?

Note that the part isn’t welded, or anchored

Is it R6 or R15?
If it is R6 add the Attachments manually.

I’m currently using an R15 rig

Well, you misspelled it.

Change the name of the Attachment to BodyBackAttachment, no BodyBackAttachement.

Or is it because of the position of the Attachment.

Ye I made a mistake in the name.
I copied the name from the Torso part of the rig