Why can't I get email from outlook.com via the mail app?

[AC Question]

I've had this account on my phone for quite a while. I sync email and contacts using Exchange (activesync). I have a Google nexus 5 running 6.0.1. Suddenly I can't sync the GMail app to my hotmail (outlook.com) account. I've verified the sync settings, they come back as fine. But when it tries to sync, it just fails. I tried just removing the account to re-add it, but I can't. I go to Accounts, click on the Exchange account, then the 3 dots for the menu, but I don't have a choice to remove the account. It does it for any of my other email accounts. I've installed the outlook app and it works fine, so I know it's not a data/connection issue. I've also cleared the cache on the phone. Any ideas? Thanks.