Minecraft Win 10 and Microsoft account?

My sister, a buddy and I just got mincer juice for win 10 …

After downloading, but only I could log in with my Microsoft or X-Box account.

But that does not work for the other two…

they constantly get a message that they can't log in…

With my sister, it is probably so that she can't sign up generally with X-Box…

Does anyone know the reason or a solution?

Inaccurate problem description. Why do not you come in? Is the password invalid?

Do you have your own account or do you use yours? The accounts are not intended for multiple people.

The best way to define the problem a bit more accurate and then google it afterwards. With your superficial description this can be anything.