Thunderbird Community Forum

I have been using Mozilla Thunderbird for decades and they have even contributed a small amount of money to Thunderbird periodically. Just within the last two or three days all of a sudden I have been unable to send emails with my phone. I receive emails, but I do not send them.

So I opened up a laptop where I did not have Thunderbird and set it up properly through Spectrum using the incoming and outgoing servers as mail.twc.com. and yes, just like on my phone. I continue to receive new emails, but even with the laptop I was unable to send an email.

I received the message"send message error sending a message failed. The message could not be sent because the connection to outgoing server smtp mail.twc.com was lost in the middle of the transaction. Try again."

I contacted Spectrum twice and both times they had me try to send a message through their Web server spectrum.net and that message did go through. Of course then their response is that this has to be a problem with the third-party app meaning Mozilla Thunderbird, and they can’t help with that at all. I sure would appreciate some help because I hate to walk away from Thunderbird as well as change my email address after all of these decades.

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.

Thunderbird has been working OK. Now, despite PC restarts and so on I get the message "mail couldn't be sent, time out error for SMTP server. I have tried changing the SMTP settings from port 465 to port 587 but no difference. If I log in to my email provider (vodafon/uniymail) I can send mails no problem. The problem is with thunderbird not sending smtp. Tried turning firewall and antivirus off, no help. Internet connection is glassfibre, internet works OK.

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)

In our organization we have moved from an on-premise mail server to M365. We've also added our new EWS-based accounts to Thunderbird. Since there are a large number of users with a significant amount of older mails they want to have access to, they have been asking how they could upload them to EWS now.

From the looks of it, using TB one can either drag and drop messages from the local folders to EWS. Would message copy/move from the local folders be faster if the EWS account was setup over IMAP, instead of over EWS? If so, we could setup another account corresponding to the same EWS identity, but over IMAP, just for the purposes of transferring messages faster.

Thanks in advance for any information provided.

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.

Rookie move. I deleted a calendar (not realizing that by deleting the calendar, which I didn't use, I was deleting all of my tasks).

Is there a way to restore the calendar?

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?

More often than it should happen, when I try to reply to a message, TB opens a screen that is surrounded by a thick white line and I can't type in the field. Why? How to I fix it?

Hi!

I'm losing my mind by the fact that you can't hold to scroll or click to toggle scroll with MMB in Thunderbird, instead it opens a new tab which is completely useless to me since I share inbox and mail reader in one screen.

Is there any way to fix or change this?

If not I'd really like to request this as an option or feature.

It appears how TB handles IMAP connections for outlook email accounts no longer works - OAuth2 connection flow broken, and this is likely due to stricter changes made on Microsoft's backend that is impacting connections going forward.

I have multiple email accounts configured and recently, I have been bombarded by login pop up - likely related to the OAuth2 authentic process.

Whilst I was able to circumvent the authentication process - i.e. not completing the flow process entirely as it expected, newly created outlook accounts appear to reveal two things:

1] There has been a recent change to the authentication process - i.e. the telling sign.

2] There is a now deeper issue when trying to connect outlook email accounts. It seems the reason why circumvention was possible with existing accounts was because they have already passed the OAuth2 process correctly - correct tokens exist. Since this won't be the case for new outlook accounts - no OAuth IMAP access token created, above error is given.

It seems the likely cause is because Thunderbird holds or requests a token that does not contain the correct IMAP audience/scope combination, and Exchange rejects it during SASL XOAUTH2 bind.

For your information, I am using the latest versions and able to configure Apple Mail client - which uses Exchange protocol (not IMAP), without issues.

I had 12 important draft messages in my "drafts" subfolder of one of my e-mail accounts. This e-mail account is a work e-mail based in Outlook, and I use Thunderbird to download those e-mails to my laptop, and to compose e-mails. The 12 messages in that Thunderbird folder suddenly disappeared, and have also disappeared from my "drafts" folder in Outlook. (The Thunderbird and the Outlook accounts are linked.) I did not change any settings. This has never happened before. Those missing e-mails do not appear in the "deleted items" folder in Thunderbird or in Outlook. It is extremely frustrating and is causing problems at work.

Oddly, my Thunderbird listing of folders still shows the number "12" next to the name of the "drafts" folder. But, there are no e-mails visible in that folder. All my other Thunderbird folders for this e-mail and for my other e-mail are working properly. Please help.

I use folder icon colors for various purposes. I prefer my color selection "menu" to look like the first included image, after I define and Add to Custom Colors.

After a restart of TB, my custom color choices go away. I believe the color choices should survive and be permanent until changed by the user. Please advise, thank you.

I updated my TB to version 148 (from 140) on a Linux Mint 22.3 - Cinnamon 64-bit. After the update, events recorded in my Gmail personal account, keep popping up and do not allow neither Dismiss or Snooze - Buttons not even work. If you close the reminder window, the Reminder window pops-up a few minutes later.

Interesting is that beyond my personal Gmail account I have a couple other in Google Workspace and they work well. It is something only related to Gmail personal.

"Read Only" in Calendar Properties is unchecked

Any advice will be highly appreciated.

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.

I dont understand this new method of sign in message you have sent, im an oldie, not an IT geek, I dont understand & very worried im going to loose access to my e-mail which has inf ormation on that i NEED

I need step by step instructions that an old guy will understand

hi today thunderbird started showing yahoo popup login and after adding credentials i always get "something went wrong.We could not sign you in. Try again from a different device." Also popup once closed it opens instantly.

i can sign in normally from browser. thunderbird version is 147

is there any fix about this?

thanks for any help

regards