my side (thumb buttons) on my mouse cant be binded for some reason and its not the mouse issue

nothing was out of the ordinary, all my keybinds were working fine but the next day I noticed that my "quit out of inventory and chat" button which was my back side button on my mouse wast working but my front button which was my first hotbar slot was working. I checked the bindings and they say "unnasigned" and when I try to assign them, the side keys wont register for some reason and I tried all my mouses and none of them work so I think its an minecraft issue.