Outlook.com authentication problem

Question

My Outlook.com mailbox works correctly in Outlook Web and the New Outlook desktop application.

However, OAuth authentication fails with Thunderbird on two different Windows 11 PCs. Blue Iris also fails to send mail using Outlook OAuth, although it successfully authenticates with Microsoft. BigPond SMTP works correctly from the same Blue Iris installation.

This appears to be an Outlook.com account or mailbox provisioning issue affecting third-party OAuth/IMAP/SMTP access rather than a local PC or network issue. Could you please check whether my mailbox has third-party IMAP/SMTP OAuth enabled and correctly provisioned?

Answer 1

@Steve Conescu said

OAuth authentication fails with Thunderbird on two different Windows 11 PCs.

I recently setup an Free/Personal outlook.com account in TBird using OAuth and it works without a hitch. If you have enabled IMAP for you outlook.com account (see below) you should not have to use App Passwords or advanced setup for an outlook.com account.

See the Answer by "Hornblower409 Jul 19, 2026" in
https://learn.microsoft.com/en-us/answers/questions/5949827/thunderbird-outlook-outgoing-connection-issue

Could you please check whether my mailbox has third-party IMAP/SMTP OAuth enabled and correctly provisioned?

To enable IMAP access to your outlook.com account:

• Logon to your outlook.com account at https://outlook.cloud.microsoft/
• File -> Settings -> Email -> Forwarding and IMAP
• If there is a [Sign in] button, click it and Sign-In (again)
• ( o) Let devices and apps use IMAP

Answer 2

Thanks, Steve for getting back.

You mean to say you have 2 accounts, one is Outlook.com and other is Bigpond, correct?

Answer 3

I don't see App Passwords in the Security Section. There is nothing to say Advanced Security either

Answer 4

Which account? I have a bigpond and an outlook account. Ideally I want to get rid of the bigpond account so assume I need to use the outlook account

Answer 5

Hi,

I'm going to run through a few steps with you. Some of these are diagnostic — they help me narrow down what's wrong, not fix it outright. So if nothing changes after a step, that's normal and expected, not a dead end. I'll keep going until we've got this resolved.

I don't think it is a provisioning issue if it is an Outlook.com account for Personal use.

If 2FA is enabled, have you tried using an App Password for the account and use that?

https://support.microsoft.com/en-us/accounts-billing/manage/how-to-get-and-use-app-passwords

1. Go to the Advanced security options of your Microsoft account dashboard and scroll down to the App passwords section. Create password
2. Enter this app password where you would enter your normal Microsoft account password in the application.

I look forward to hearing from you to get the results of the troubleshooting.