To learn more about modern authentication, visit:
In order for Office clients to use modern authentication flows, the Office 365 tenant needs to support modern authentication flows. You can find more details here -
The Office 365 tenant/resource host (Exchange Online, SharePoint Online and Skype for Business Online) will need to be configured to accept a modern authentication connection. Here is the per service state of modern authentication by default :
Exchange Online - OFF by default.
SharePoint Online - ON by default.
Skype for Business Online - OFF by default.
This article explains how to enable your Exchange Online tenant to support modern authentication.
Get-OrganizationConfig | ft name, *OAuth*
If your Exchange Online tenant was previously enabled as a part of the Private Preview or Public Preview programs, no action is needed at this time. You can verify that your tenant is configured to support modern authentication by following Step 3 above.
Visit https://aka.ms/SkypeModernAuth. We recommend that you enable your Exchange Online tenant for modern authentication
prior to enabling Skype for Business Online for modern authentication.
Yes, production support is available for all tenants enabled for modern authentication.