Why won't Xbox Live let me log in to my account when I press the 'Log In' button?

Hi! I'm trying to change my Minecraft username (bedrock), so I looked it up and saw that I needed to do it via Xbox. Well, I go to the website and press the sign-in button at the top, sign into my account, and then it loads and I'm redirected back to the same page, except I'm not signed in. I try over and over again, but it does nothing? I'm never actually signed in, even when I press the 'Log In' button in the top-right corner. And yes, I've already tried clearing my cache and cookies; there's never an error code either. I've also already tried closing the page and reopening, as well as restarting my laptop.

:)