Can't create character, marketplace also says invalid session

The past month or so, even after the 1.19 update any time I try to change a skin, it doesn't let me create a character. When I click the 'Create Character' icon nothing happens and appears to be grey. Even when clicking other options like the capes, emotes, classic skins, etc, nothing happens. The marketplace also says invalid session. I restarted my game, uninstalled and reinstalled it, and updated it, and nothing has worked. It logs me in and I'm able to play online servers and with friends and everything. but my skin is just default skin like Steve or Alex.