Outlook | Web | Outlook.com | Email
Sending, receiving, and organizing email in Outlook.com
can I get an update how did you remove the account(affected account) from thunderbird? If you recreated it what happened?
outlook.com smtp
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Tony Larmer
0
Reputation points
I have 2 outlook.com email accounts and use Thunderbird as a client. One account works perfectly but although I can receive emails I can't send from the other, the smtp server refuses the connection. All settings are identical for both accounts and I can send when logged in on the web. I've double checked that the password is correct.
Outlook | Web | Outlook.com | Email
5 answers
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IGYQ 21,360 Reputation points Independent Advisor2026-08-03T17:02:55.18+00:00 Okay let's try this by removing the affected account first.
To set this up correctly, remove the Outlook.com account from Thunderbird (or your mail app) and add it again. When prompted for authentication, select OAuth2 and enter your email address. Do not select "Normal password" and do not manually create or save a password entry. A Microsoft sign-in window should appear; complete the sign-in there and approve the requested access. Once everything is done you can go ahead check if there will be any difference.
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Tony Larmer 0 Reputation points
2026-08-01T16:34:43.31+00:00 Login to server smtp-mail.outlook.com failed.
Sending of the message failed.
Unable to authenticate to Outgoing server (SMTP) . Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)'.
smtp-mail.outlook.com
Port 587
STARTTLS
OAuth2
Exactly the same settings on my other Outlook.com email and that works.
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Tony Larmer 0 Reputation points
2026-08-01T16:32:03.0166667+00:00 Login to server smtp-mail.outlook.com failed.
Sending of the message failed.
Unable to authenticate to Outgoing server (SMTP) . Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)'.
Port 587
STARTTLS
OAuth2
Exactly the same settings on my other Outlook.com email and that works.
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IGYQ 21,360 Reputation points Independent Advisor
2026-08-01T15:01:35.95+00:00 Hi!
Welcome to the Microsoft Q&A forum.
To narrow down the cause, could you answer these questions?
What is the exact SMTP error message Thunderbird displays? (For example, "Authentication failed", "Connection refused", or "5.7.x" error.)
Is the affected account an Outlook.com/Hotmail/Live.com personal account, or a Microsoft 365/Exchange account?
Which SMTP server name is configured (smtp.office365.com, smtp-mail.outlook.com, or something else)?