Refreshing your profile has proven successful if you encounter this code 80048821
You do not need to be signed into your xbox to follow these steps.
1. From the home dashboard on the xbox, go into the Settings hub, then the System tile, then Storage.
2. Here select your main storage device (usually a hard drive or a memory unit), then select Profile or Gamer Profiles.
3. Find and select your profile and delete PROFILE ONLY! Do NOT delete profile and items as this will delete content you want/need. Then back out to the list of storage devices.
4. Press "Y" on your storage device (instead of "A" like you did before). Under device options choose Clear System Cache. Once you've done this, power off your xbox and unplug it from the power brick (or from the wall, your choice) and leave unplugged for 30 seconds.
5. When you power back on, do not sign in, instead Download your profile using your Microsoft Account and your new password.
You should now have access to your account again.