Thunderbird Community Forum

Hi everyone! Why do I get an error when I try to download messages - "Failed to save message. Check the spelling of the file name, wait a while, and try again"

And the most annoying thing is that after this error, downloading other letters stops and you have to manually search for that very letter, although there may be thousands of them... Please fix this!

I already have two Exchange email accounts using Exquilla that were created in earlier T-bird versions, they work in the latest version as well. I am trying to add a third exchange account, I enter the email and password do auto discover and get the following error; Invalid or missing password: password does not exist in the directory for this user. Trace ID: b2766d8c-6b02-4879-ab77-e30177281600 Correlation ID: 220ef2bd-c4b2-42a9-9414-d4f7bc0dae35 Timestamp: 2026-03-06 02:43:34Z

An Autodiscover site was found, but we could not find a usable entry. This is probably because your server does not support Exchange Web Services (EWS). If your server does not support EWS, then ExQuilla will not work for you. If you believe this to be in error, try manually entering the EWS URL.

I know the message is wrong since I have two accounts that function. I have gone through the manual configuration as indicated online and still have no success just says "URL test failed". I was hoping this latest version would have another way to be able to enter information to get around the failure. Any guidance is greatly appreciated.

Edition Windows 10 IoT Enterprise LTSC Version 21H2 Installiert am ‎18.‎09.‎2025 Betriebssystembuild 19044.6937

Thunderbird Version 148.0 von Feb 2026

bis zum 5.3.2026 funktoinierte TB einwandfrei, aber seit gestern kann ich keine Mails mehr versenden, folgende Fehlermeldung wird angezeigt siehe Bild Hochgeladen. Gestern wurde die IP 18.195.155.157 angezeigt, heute 3.70.126.251

Empfangen von E-Mails hat funktioniert nur beim Senden oder Weiterleiten kommt die Fehlermeldung.

es Spielt auch keine Rolle von welchem Konto ich Mails verfasse, ob T-online,Web oder Agenturserver

Benutze den Acount auch auf einem Laptop mit W11, dort funktioniert alles,

Die SMTP Einstellungen hab ich überprüft, Laptop und diesem PC sind identisch (Hatte ja auch keine Änderung in diesem Bereich durchgeführt)

Возникает ошибка:

Ошибка отправления сообщения. Сообщение не может быть отправлено, так как не удалось установить соединение с Сервером исходящей почты (SMTP) «smtp.gmail.com». Сервер может быть недоступен или отказывать в соединении по SMTP. Убедитесь, что указали корректные параметры Сервера исходящей почты (SMTP) и попробуйте снова.

Hi

When Thunderbird is started maximized it overlap taskbar if is set to hide and taskbar won't show until Thunderbird is minimized and maximized. Another way is to press the Win key two times. Then the hided taskbar can be shown/use. The same thing happens to Firefox. Only when is first started. Then if Firefox is minimized and maximized, press Win key two times, press F11 two times then the hided taskbar show/hide normal.

It is a setting that can be changed to start Thunderbird and Firefox in full screen and do not overlap hided taskbar?

Can not send emails to a newly created outlook.com (free) account. Have tried dozens of different settings, approaches.

My current setup:

 - windows 10
 - thunderbird 140.8.0esr (64-bit),  numerous previous versions also do not work
 - outlook.com (free) account mail provider
 - POP3 enabled (tried IMAP enabling also) on outlook.com account
 - no 2FA or 2FA enabled on outlook.com account, no difference
 - outlook.com web access works fine
 - followed instructions in mozilla support article Microsoft OAuth Authentication and Thunderbird in 2024 
      (https://support.mozilla.org/en-US/kb/microsoft-oauth-authentication-and-thunderbird-202)
 - have done a fresh install on a new machine without an existing profile.
 - have tried various microsoft servers, have tried oauth2, normal password
 - thunderbird account creation works just fine.
 - server settings and SMTP settings match as recommended by support article noted above
    SMTP server settings
        server name: smtp-mail.outlook.com  
        port: 587
        connection: STARTTLS
        authentication: OAUTH2
        user:  xxxxxxxx@outlook.com

symptoms:

 - receiving(downloading) emails works fine.
 - sending emails fails with following messages
     Login to server smtp-mail.outlook.com with username  xxxxxx@outlook.com    failed    followed by 
           Unable to authenticate to Outgoing server (SMTP) . Please check the password and verify the 
             'Authentication method' in 'Account Settings | Outgoing server (SMTP)'

Many people seem to be having this issue with no resolution.

Please help.

When I go into my email program it asks for a password over and over again. it doesn't matter what password I put in, nothing works. Thunderbird has tried to send codes, but they don't go through to my email program. I have used my iPad with a different email address to check some things and go to Shaw Webmail to retrieve my emails. I need it to work as I have lots of files on there that I use often with a volunteer organization among others.

I have never deleted so many emails at one time, around 500. Did I exceed the limits of Thunderbird? I cannot log on. Cannot see new emails. I have been on emailsrvr.com and did verify my passwords. Thank You

Hi I keep getting the message "Unable to connect to your IMAP server". I have reduced the number of 'server connections to cache' from the default 5 down to 1. Thanks

I can receive mail fine. Cannot send mail on gmx.co.uk acct, but gmx.net works on oauth2. But oauth2 is missing on gmx.co.uk It's just not on the pulldown. I tried a new thunderbird acct for gmx.co.uk but oauth2 is still missing.

Can get(POP3), but can not send emails to a newly created personal outlook.com account.

the following error occurs when trying to send mail: Unable to authenticate to Outgoing server (SMTP) . Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)

all my setting are correct per thunderbird and microsoft:

  (smtp-mail.outlook.com, port 587,  STARTTLS, OAUTH2, xxxxx@outlook.com)

thunderbird error log file contains the following: . . . mailnews.smtp: S: 535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information. [CH5P220CA0005.NAMP220.PROD.OUTLOOK.COM 2026-02-28T23:29:21.878Z 08DE7703D4D1982A]

SmtpClient.sys.mjs:452:17 mailnews.smtp: Command failed: 535 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information. [CH5P220CA0005.NAMP220.PROD.OUTLOOK.COM 2026-02-28T23:29:21.878Z 08DE7703D4D1982A]; currentAction=_actionAUTH_XOAUTH2 SmtpClient.sys.mjs:578:19 mailnews.smtp: Error during AUTH XOAUTH2, sending empty response . . .

Based on my understanding its seems thunderbird is using SMTP AUTH instead of OAUTH2 as required for newer personal outlook.com accounts. Is my assessment correct? If so, is there a fix?