Wont let me change skin and go to marketplace.

Everytime i go into Minecraft: Bedrock Edition it say "Invalid Session." I have restarted it and re installed it but nothing happened. I cant change my skin or go to market place. It has been here since i have bought the game. The most newest bug to it is that it now says" playfab environment mismatch". It switches between "Session invalid" and "playfab environment mismatch." Please fix and thank you. my user is Retrotaco87