Basic Authentication Transition Guidance

Microsoft is ending support for the legacy Basic Authentication in Office 365. As a result, older email clients that use Basic Authentication will no longer be compatible with Office 365 services. This change impacts all devices, including desktops, laptops, smartphones and tablets.

What is changing?

Although it is simple to set up and use, Basic Authentication makes it easier for attackers to capture users’ login information and increases the chance of this login being used to access multiple systems. Because of this security vulnerability, Microsoft has announced that it will no longer support Basic Authentication for Office 365 email, in favor of the more secure Modern Authentication. On March 28, 2021, the University of Chicago will turn off Basic Authentication for all devices accessing University Office 365 email. If you are interested in knowing more, please visit our Modern Authentication FAQ.

For reference, the following operating system versions and email applications support Modern Authentication.

Device Type Operating System Version Email Application
Windows 8.0 or later Outlook 2016
Outlook 2019
Outlook – Office 365
Windows 10 Mail
Thunderbird V78 or later
Mac 10.14 or later Apple Mail
Outlook 2019 for Mac
Outlook for Mac – Office 365
10.13 or earlier Thunderbird v78 or later
iOS (iPhone, iPad) 11.3.1 or earlier Apple Mail
Outlook for iOS
Android 8.0 or later Outlook for Android
Linux Outlook on the web
If you are using one of the following types of email protocols, you may attempt to fix the problem yourself. Otherwise, please feel welcome to contact Social Sciences Computing Services to help you apply the fix.


  1. Exchange Web Services
  2. IMAP, POP, Authenticated SMTP
  3. Active Sync
  4. MAPI over HTTP