Office 365 Multi-Factor Authentication
22/04/2016

How often will you be prompted for MFA in Outlook for Office 365?




When using Multi-factor authentication in Office 365 something that is good to understand is how often you can expect to be prompted to enter the second factor.


Microsoft Office 365 session timeouts article below explains how this works in the Azure Active Directory with modern authentication section: Session timeouts for Microsoft Office 365



When you successfully authenticate you will receive a access token and a refresh token to be able access Office 365 services . The access token is only valid for an hour and then the refresh token is used to obtain a new access token if the initial authentication is still valid.



The Refresh token is valid for 14 days but if you are continuously using your mailbox during this period it can last up to 90 days.



So it could be you are not asked for Multi-factor authentication again for up to 90 days in Outlook.



Things that could force you to re-authenticate:



  • If you sign in and out again in Office clients
  • Don't login for 14 days on that device
  • Change your password
  • Administrators can apply conditional policies to restrict the resource the user is trying to access
  • Swap between Office 365 accounts


More information on how to enabled modern authentication in Office 365 can be found below:


How modern authentication works for Office 2013 and Office 2016 client apps

Microsoft 365 | July 2019 updates
14/08/2019

Microsoft 365 | July 2019 updates

14/08/2019
This month's Microsoft 365 updates enable your business to have better security and still maintain productivit...
Microsoft Azure | July 2019 updates
13/08/2019

Microsoft Azure | July 2019 updates

13/08/2019
This month's latest updates for Microsoft Azure include their new Azure Cost Management tool which is a handy ...
Microsoft Teams | July 2019 update
12/08/2019

Microsoft Teams | July 2019 update

12/08/2019
Discover the latest updates to hit Microsoft Teams this month, including changes to its chat and calling funct...