Email stopped syncing, authentication fails during new setup.

The server may be down for your email account

 

Do you have any problem signing into the web interface for your account?:
https://login.live.com/login.srf?wa...XT=out&lw=1&fl=dob,flname,wld&cobrandid=90015

What email app are you using? The default email app on your device or have you installed a third-party email client like the Outlook app?

 

Good news there's not anything device specific with this email access issue then. If you prefer to keep using the stock email app, try going to your Settings >> Apps menu, find and open the email app entry, and then find the 'Clear data' option. Using that will wipe all the app's settings and configurations, along with the app's cache, essentially returning the app back to its original, first time use state. If you're still having an issue with setting up your email account after that, you could try to just manually add your account, using Microsoft's suggested settings:
https://www.serversettings.email/live.com-email-server-settings-imap.php#android

But in most situations, most third-party email apps will have a bigger feature set and more options to alter the user interface, so you might want to just disable the stock email app and install a more robust email client -- the Outlook app is from Microsoft too so it integrates well with its other online services, or if you prefer to go outside the MS realm, a more independent option that gets good reviews is the Blue Mail app.