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Sending newOutlook mail from TB

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  • Last reply by david

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Hello, I recently replaced my old PC with new desktop running WIN 11. Although I am able to receive Outlook email. However, when I attempt to send mail from my Outlook address I receive an error message: "Unable to authenticate Outgoing server smtp.office365.com..." The smtp settings are attached. Firewall - Windows firewall Antivirus - MS Defender Antivirus OS - Win 11 v 23H2 Thunderbird - 129.0.1

Thanks, Richard

Hello, I recently replaced my old PC with new desktop running WIN 11. Although I am able to receive Outlook email. However, when I attempt to send mail from my Outlook address I receive an error message: "Unable to authenticate Outgoing server smtp.office365.com..." The smtp settings are attached. Firewall - Windows firewall Antivirus - MS Defender Antivirus OS - Win 11 v 23H2 Thunderbird - 129.0.1 Thanks, Richard
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Your settings are the same as mine and all is well for me. I'm on Linux rather than Windows but I can't see that making any odds.

When you set Thunderbird up did you configure your account manually or via the wizard? If you did it manually it may be worth deleting what's in the boxes and entering it again just in case there's a space before or after something that we can't see or what looks like a lower-case l (l) actually being a capital I (I) or vice versa. It also may refresh something and get it going.

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Update to the problem statement: This issue cannot be resolved at this time, had to switch to new Outlook for email. The tech at the shop where I purchased my desktop troubleshot the problem using remote access. After checking all settings and referring to Mozilla resources determined that Mozilla Thunderbird software has not yet been updated to be compatible to the new Microsoft authentication process.

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That is wrong. I have been using Outlook with Oauth2 and thunderbird for months, and we have assisted many here in updating their setting to Oauth2. You may need someone else to assist you. Did you include your full email address in the user field?

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