A few months ago (probably December) there was this glitch where you could give mobs immortality by splashing them with harm and health at the same time, so me and my friend tried it on my character in my survival world and it bugged out my respawn and I had to restart my game. after I logged into my game my skins/dressing room stopped working and the market place wouldn't open with the text "Invalid session (Try restarting your game)" on it when I tried and it has been happening ever since, and every now and then I gain access to my skins and have a valid games session but sometimes it will happen again randomly and it usually comes back after a game restart and restarting doesn't fix it. It hasn't really bothered me before but now it seems my friend can't join my world and I can't join his due to an invalid game session, it doesn't stop me from joining servers and realms though. This glitch also stays through out versions so even though it happened on PC if I go to Xbox or my phone the same thing happens.
The first screenshot is my invalid session, the second is my dressing room and the third is what happens when I try to join a friends world.