I cant sign in on my xbox one.

so my brother cant sign in on our xbox one.

when he goes to sign in to his account it will ask him "who are you?" (with the prompts "looks good" and "remind me later" NOTE: these prompts only appear 1 out of 5 times, every other time the screen will pop up then disappear)

when he tries to select "looks good" the screen will load then go back to the account selection screen. likewise with "remind me later"

further investigation has shown that almost all of the accounts suffer from this issue (save for mine and my littlest brothers account)

i dont know if this is some kind of software update that me and my brother missed but an answer would be much appreciated.
thank you.