Before you make changes to your account on your device or application, you can check whether basic or modern authentication is in use. This step is recommended for macOS/iOS Mail and optional for other email apps. 

Outlook for Windows 2016 or higher

1. Launch Outlook
2. Press and hold the Control key and right-click the Outlook tray icon
3. Select Connection Status from the popup menu
4. Select the General tab
5. Review the Authn column
   
   • Clear indicates a basic authentication connection
   • Bearer indicates a modern authentication connection
6. If any connections are listed as Clear, continue with the remaining steps before removing and re-adding the Exchange account
7. Look for the the following registry keys:

   HKCU\SOFTWARE\Microsoft\Office\15.0\Common\Identity\EnableADAL
   HKCU\SOFTWARE\Microsoft\Office\15.0\Common\Identity\Version
   HKCU\SOFTWARE\Microsoft\Office\16.0\Common\Identity\EnableADAL
   HKCU\SOFTWARE\Microsoft\Office\16.0\Common\Identity\Version

8. If any of the keys exist, set their DWORD values to 1
9. If any connections were listed as Clear, see Outlook for Windows: Add/Remove Exchange Account
   

Outlook for Windows - IMAP Accounts

1. Click File
2. Click the Account Settings button
3. Select Account Settings from the drop-down menu
   
4. IMAP accounts appear with a type of IMAP/SMTP
5. The Exchange account must be removed and added back. See IMAP: Add/Remove Exchange Account

Outlook for Mac 2019 or higher

1. From the Tools menu select Accounts
2. Select email account in the left pane
   
   
3. Check the Password field
   
   • If the Password field is blank or says "Microsoft sync technology," Outlook is using modern authentication.  No further action required.
   • If the password field is not blank, assume basic authentication is in use. The Exchange account must be removed and added back. See Outlook for Mac: Add/Remove Exchange Account.

macOS Mail

1. From the Mail menu, select Preferences
2. Select the Accounts toolbar icon
3. Select your email account from the left pane
4. If the Password field is visible and is not blank, Basic Authentication is in use. The Exchange account must be removed and added back. See macOS Mail: Add/Remove Exchange Account.

iOS Mail

1. Open the Settings app
2. Find the iOS version installed on your device, go to General, then tap About.
3. For iOS 14 or later, select Mail > Accounts. For iOS 13 and below, select Passwords & Accounts.
4. Select your email account
5. Tap Account
6. In the Account detail window, if Server and Password fields appear Basic Authentication is in use. The Exchange account must be removed and added back. See iOS Mail: Add/Remove Exchange Account

Outlook for Android

Basic authentication settings are not visible. Remove and add the account back.  See Outlook for Android: Add/Remove Exchange Account

Outlook for iOS

1. Open the Outlook app
2. Tap the user icon at the upper left
3. Select the gear at lower left
4. Select your account
5. At the bottom of the screen, if Edit Login Information appears, Basic Authentication is in use. The Exchange account must be removed and added back. See Outlook for iOS: Add/Remove Exchange Account

Thunderbird 78.0 or higher

1. From the Tools menu select Account Settings
2. Select Server Setting from the left pane
3. In the Security Settings section, if Authentication Method is Normal Password, Basic Authentication is in use. The Exchange account must be updated.  See Thunderbird: Update Princeton Exchange Account to Modern Authentication