Error when unable to change skin in the locker room

​The problem is that I can't change the skin. I go to the locker room and the default Minecraft skins appear, and if I click on the options, only the default skins remain. I can't buy, choose, or change skins, and in the world and on the main screen, there is always a default Minecraft skin. The problem has been going on for several months now and has not been resolved.