Microsoft 365 (Thunderbird) - Configure Modern Authentication

These instructions are for version of Thunderbird 77.0b1 or later, which supports OAuth2 modern authentication. To see your current version, press ALT+H and ALT+A.

If after going through this page, you're still experiencing trouble, visit Thunderbird's Support Page for more information. 

Configure Thunderbird for Microsoft 365

  1. Launch Thunderbird to bring up the main Thunderbird interface.
  2. If you have other accounts configured, you can navigate here by clicking on Local Folders on the left-hand side. Select Email under the Setup Another Account section in the main window.
  3. On the Mail Account Setup window, enter information into the available fields as follows:
    • Your name: Your name as you'd like it to appear
    • Email Address:
      • NetID Account: Enter 
      • Service Account: Enter
        • For example, if your username was helpdesk-team-kb and the domain was doit, you'd type
        • For multi-level domains,, use the following format:
    • Important: do not enter in your password on this login screen. Only enter your email address and name.

    • Note: If you don't know whether you are attempting to configure a NetID account or a Service account, please contact your domain administrator.

    Textboxes for name and email address
  4. Click Continue
  5. Thunderbird should automatically discover IMAP as the available configuration and fill in the server settings necessary for your account:
    • Incoming
    • Outgoing
    • Username
    IMAP Configuration Details
  6. Click Done to confirm the creation of your account. You will be prompted to complete Two Factor Authentication. Complete this to continue.
  7. For a service account, you will need to enter username_domain as the NetID (example: kb-helpdesk-team_doit), and you will need a password. If the service account does not have a password, you can request one at Microsoft 365 - Reset Service Account Password .

    NetID pop-up

    A window will pop up with a Permissions Request. Click Accept.

    Permissions Request pop-up

  8. Click Finish.

    Finish button

If you are experiencing the issues after the above configuration attempt, use the following steps to verify that your server settings are correct. You will most likely not need go through these steps because these settings should be the default.
  1. Navigate to Account Settings > Server Settings > Security Settings > Authentication Method and select OAuth2 from the Authentication Method dropdown.

    Server Settings

  2. Navigate to Outgoing Server on the bottom of the left-hand panel of the account settings screen.
  3. Select the University of Wisconsin M365 smtp server and click edit on the righthand side

    Security Settings

  4. Change the Authentication method to OAuth2  to the following and then click OK:
    • Description: University of Wisconsin M365 (
    • Server Name:
    • Port: 587 (default)
    • User Name: your username
    • Authentication Method: OAuth2
    • Connection Security: STARTTLS
  5. Now, when you attempt to view your inbox, instead of being prompted for your password by Thunderbird, you will be redirected to authenticate through Duo.
  6. After authenticating in step 5, the setup is complete. Email data will take some time to sync. BE PATIENT.

You can get to the configuration settings by:

  1. Click Tools on the top menu bar (or the key combination ALT+T)
  2. Click Account Settings

Important Additional Steps to Complete Before Using Thunderbird

  • Reconfigure folder mapping:

    Clients configured using Microsoft Exchange protocol use different folders for some of the primary mail folders. For consistency, we highly recommend that you configure Thunderbird to use these same folders. This will make it less confusing if you also use the web client for Microsoft 365 or a different desktop client that is using the Exchange protocol.

    1. Right-click on your Microsoft 365 account and select "Subscribe..." from the drop-down menu.

      Reconfigure Folder Mapping - select Subscribe menu option

    2. Place a check-mark within the box next to each of these folders: "Drafts | Deleted Items | Sent Items".
    3. Click Subscribe button.

      folder subscribe screen

    4. Click OK button.
    5. Right-click on your Microsoft 365 account and select "Settings..." from the drop-down menu.

      account settings menu selection

    6. Under your Microsoft 365 account, select "Server Settings".
    7. Within 'Server Settings | When I delete a message' section, select "Move it to this folder:" and use the text box next to this setting to select the "Deleted Items" folder.

      server settings options

    8. Under your Microsoft 365 account, select "Copies & Folders".
    9. Within 'When sending messages, automatically | Place a copy in:' section, select "Other" and use the text box next to this setting to select the "Sent Items" folder within your Microsoft 365 account.

      sending messages options

    10. Make sure "Drafts" folder is selected within your Microsoft 365 account under 'Drafts and Templates'.

      drafts and template options

    11. Click the OK button.
    12. Restart Thunderbird
  • Disable the adaptive junk mail controls:

    Microsoft 365 server side junk/spam filtering is already enabled for all Microsoft 365 accounts.

    1. Right click on the email address you just configured in the left-hand pane.
    2. Click on Settings.
    3. Click Junk Settings from the left-hand option pane.

      Click Junk Settings

    4. Uncheck the box for Enable adaptive junk mail controls for this account.

      Disable Adaptive Junk Settings

    5. Click the OK button.

Configure Access to the Campus Directory (Whitepages)

KeywordsModern Authentication thunderbird beta office 365 smtp folders server junk mail sent items deleted configure OAuth2 2 factor Authentication 2FA Whitepages campus directoryDoc ID102005
OwnerHelp Desk KB TeamGroupDoIT Help Desk
Created2020-05-12 12:15:18Updated2023-09-10 16:24:03
SitesDoIT Help Desk, Microsoft 365
Feedback  128   73