I am an emeritus professor using the UVM email account X@uvm.edu<mailto:X@uvm.edu>, which I have used for many years. I use Mozilla Thunderbird (current version, “E… (read more)
I am an emeritus professor using the UVM email account X@uvm.edu<mailto:X@uvm.edu>, which I have used for many years. I use Mozilla Thunderbird (current version, “Eclipse”) as my email client and my account is configured for UVM’s Microsoft 365/Exchange Online service.
After my most recent required yearly password change, although I can still receive email in Thunderbird, I can no longer send email. When I attempt to send a message, I consistently see this error:
“Login to account ‘smtp.office365.com’ failed.
Login to server smtp.office365.com with username tosler@uvm.edu<mailto:X@uvm.edu> failed.”
Here are my current settings:
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Incoming (IMAP):
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Server: outlook.office365.com
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Port: 993
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Connection security: SSL/TLS
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Authentication method: OAuth2
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Username: tosler@uvm.edu
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Outgoing (SMTP):
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Server: smtp.office365.com (I have also tested smtp.uvm.edu with the same result)
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Port: 587
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Connection security: STARTTLS
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Authentication method: OAuth2
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Username: X@uvm.edu
I have reinstalled Thunderbird, and I have removed all saved passwords and tokens for outlook.office365.com and smtp.office365.com, restarted the program, and completed the Microsoft/UVM sign‑in prompt again. IMAP continues to work and mail arrives normally, but SMTP authentication still fails with the error above.
Because:
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The configuration matches Microsoft 365/Exchange Online client‑submission settings, and
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IMAP with OAuth2 works, while SMTP with OAuth2 fails,
it appears that this may be a server‑side policy or mailbox setting, rather than a client configuration problem. What are my options? Does the University of Vermont have to change some setting on their end on my behalf? Thanks. -turner
(PII redacted by moderator)
