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Unable to send emails through SMTP anymore

  • 9 replies
  • 2 have this problem
  • 22 views
  • Last reply by sfhowes

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Hi,

I have been unable to send emails with SMTP for the last couple of days, although it previously worked without problems.

System: macOS 10.14

SMTP Settings: Server: smtp.office365.com Port: 587 Connection Security: STARTTLS Authentication Method: OAuth2 Username: full email address

When sending an email, I get a "Login to account XXX failed. Login to server smtp.office365.com with username YYY failed".

Things I have already tried: (1) if I try to send email directly from Outlook, it works. (2) removing the SMTP server in TB and adding it again didn't work. (3) removing saved passwords in TB: if I go to Preferences -> Privacy -> Saved passwords, there is one line only:

oauth://login.microsoftonline.com (https://outlook.office365.com/IMAP.AccessAsUser.All https://outlook.office365.com/POP.AccessAsUser.All https://outlook.office365.com/SMTP.Send offline_access)

Removing that line and restarting TB will result in a popup taking me to institutional login, where I enter my email and pwd. I login without problems, but I still get the same error.

IMAP is working fine, so I am a bit unsure what the issue might be. I am not sure if SMTP passwords are stored somewhere else and that is creating problems, or if my prefs.js file is somehow corrupted (nothing obvious I could tell by reading it).

Any help is greatly appreciated, thanks in advance.

Jose

All Replies (9)

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If the authentication on the incoming and outgoing is OAuth2, there is a single oauth:// token in Saved Passwords. Confirm that cookies are accepted in TB Preferences, as this is required for OAuth.

See also: https://support.mozilla.org/en-US/questions/1359123

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Thank you for the quick reply. Cookies are accepted in TB preferences. I read the ideas on that thread (https://support.mozilla.org/en-US/questions/1359123):

- Setting General.UserAgent.CompatMode.Firefox to True didn't work. - Eightwone article (https://eightwone.com/2020/07/01/configuring-exchange-account-with-imap-oauth2/#comment-267736) mentioned in the thread: if I understand correctly, this refers to my institution authorizing my sending emails through SMTP (SMTP AUTH permissions being set with Set-CASMailbox -SmtpClientAuthenticationDisabled $false). This was done back in March and until a couple days ago it was working, I was able to send emails using the same configuration I currently have. I check with my institution this morning and they have not changed settings, so I assume the issue is on my side.

Any other thoughts? Thanks again for your time.

Jose

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If it was working until recently, I would look at any other external factor that might have changed, such as possibly a security/antivirus app that updated, and was configured to scan outgoing mail. Did the issue occur after a TB update? Look at the Update History in Preferences/General/Updates.

https://support.mozilla.org/en-US/questions/1323481

https://support.mozilla.org/en-US/questions/1306336

Modified by sfhowes

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No recent changes to security/antivirus, and TB's last update is from Nov 20.

Something I just remembered: the day it stopped working, I was connected to a VPN, which I saw can create issues (https://support.mozilla.org/en-US/questions/1206707). However, I have not being connected to the VPN since, and I am still unable to send emails.

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The VPN might have messed up the proxy settings in TB. In Preferences/General/Network & Disk Space, Connection, Settings, it should be 'No proxy'.

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Connection was set to 'Use system proxy settings', I changed it to 'No proxy' but that didn't work either.

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Any other ideas of what could I try? Anything in the log files I could look for, additional settings...?

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It seems there is no solution for my problem, so unfortunately I'll have to stop using Thunderbird after 15 years...

Thanks again for your help, I understand support is done by volunteers and I appreciate your time.

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