launcher and game won't recognize that I bought minecraft windows 10 edition

I bought minecraft windows 10 for my computer and for the past 6 months it has had no problems and now it thinks that I have not bought the game in the launcher and in the game. I just want to play minecraft again, because it won't let me invite my friends and it won't let me join servers. plus I can't even export the worlds that I have because it only allows me to delete the worlds