My xbox app doesn't work, it dosen't allow me to sign in... what i should do?

I created another account, same result. Doesn't allow the fantasy football league. I used a friend's account on the nfl app to ensure it wasn't my credentials. It did not allow me to sign in, I was able to sign in my account on their xbox. This is simply
a problem with the Xbox.

I may have found a solution to this problem. It may not work for everyone; I have no idea. What I did that somehow by a FAR FETCHED MIRACLE worked was simply logging into my XBOX account online since the app on my computer was not allowing me to. I then
made sure my account settings on my computer allowed me to always be notified of any changes made. After that, I closed out all my browsers and then restarted my computer. Afterwards, I opened up the XBOXmahjong app, and it asked for permission to update and
use my Microsoft XBOX account. I allowed this and clicked okay. It then signed me in, and the XBOX app signed me in as well upon opening. I hope this helps!!!!

It's Already on FAT32.

When I drag the file which contains music, it says it dosen't allow me and there is no space left.

Which cleary is because its an 16GB USB that I just bought yesterday.

But if it dosen't work, then I just have to carry on.

Good afternoon I've actually tried this and it doesn't even work I've deleted the profile from my Xbox and it still doesn't do that and I have a 360 the one that I used to play a lot of games on and it's still not letting me sign in I deleted it I got rid of all the cache deleted all the games and everything and some of them I moved and it's still not allowing me even though I put in the app password

This is what worked for me: Go to settings > Power & Start-Up > Power Mode: Energy Save

Turn off then turn on the system

It should work. Doing this allows the xbox to reboot the TV app