Even if most people use modern authentication for connecting with Exchange Online, some users still have to use app passwords to enable connections from Outlook.
For tenants created after August 2017, modern authentication is enabled by default, but some admins have it turned off.
To enable modern authentication for Exchange Online, follow these steps:
- Click on Modern authentication | Microsoft.com or go to admin.microsoft.com, then Settings, Org Settings, Modern authentication.
- Select “Turn on modern authentication for Outlook 2013 for Windows and later (recommended)“.
- Let all the basic authentication protocols selected.
- Click “Save“.
You should aim to disable all the basic authentication protocols as soon as possible.
To enable modern authentication on Outlook 2013, click on the following guide: