Arch Linux

herOldMan

Member

Registered: 2013-10-11

Posts: 163

[Solved] Thunderbird - Outlook365 SMTP problem

Hi,

Our company recently changed our email server to a multi-user, Office365 account. I currently have to use the browser to send email because I cannot get the Thunderbird outgoing server to authenticate properly. Incoming mail is working fine.

The SMTP settings are (as specified by Microsoft):
  Server: smtp.office365.com
  Port 587
  Connection Security: STARTTLS
  Authentication Method: OAuth2

When the smtp connection is made for the first time, Thunderbird's internal browser opens and asks for the account password. Subsequently, upon entering the correct password, it sends me a text with the six-digit code, which I enter. All appears exactly as it should but, as the send is further processed, it hangs... eventually throwing an error that the user/password combination is invalid.

I should note that I have attempted multiple other approaches including other authentication methods and security protocols The settings above are the only ones that reached the usual, first-time authentication browser dialog that Outlook users see.

How can I get Thunderbird to send my mail from this Office365 account? Is there a configuration detail I am not addressing?

Last edited by herOldMan (2022-01-06 01:06:00)

herOldMan

Member

Registered: 2013-10-11

Posts: 163

Re: [Solved] Thunderbird - Outlook365 SMTP problem

In the spirit of closing the loop so others can avoid the trouble I had with this, I added a troubleshooting item to the Thunderbird Arch Wiki page.

Lone_Wolf

Administrator

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 15,309

Re: [Solved] Thunderbird - Outlook365 SMTP problem

Thanks for solving this and informing us of it .

I wonder what standard "modern email clients" written by microsoft use since they don't use IMAP / POP3 / SMTP .

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progandy

Member

Registered: 2012-05-17

Posts: 5,321

Re: [Solved] Thunderbird - Outlook365 SMTP problem

I wonder what standard "modern email clients" written by microsoft use since they don't use IMAP / POP3 / SMTP .

They use OWA or EWS or EWS/ActiveSync or the Outlook protocol to talk with MS Exchange servers.

Google also has their own protocol that is preferred over imap and some of those privacy, encryption focused providers like proton, or tutanota do not have IMAP/SMTP at all. It gets really ugly when that is combined with OAuth client IDs so the mail server can limit your client choice even among those that support the API.

Last edited by progandy (2022-01-06 13:52:45)

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