Microsoft has identified the root cause of the MFA login issue and is continuing to monitor the situation to ensure impact has been remediated. Status is still being updated at https://status.office365.com/.
Posted 21 days ago. Nov 20, 2018 - 09:09 CST
Microsoft is currently experiencing Multi-Factor Authentication (MFA) issues with Office 365 accounts, resulting in the inability for some users to login. Microsoft is aware of the issue and is updating status at https://status.office365.com/.