Thunderbird Community Forum

On my Windows 11 PC, when I open my Thunderbird Address Book and click on any entry, or right-click and select any option, a solid grey veneer overlays the Address Book window, and nothing else happens: The feature hangs. I can close the window and continue to use Thunderbird, but all I can do in the Address Book is scroll through the names and email addresses. When this first happened, I updated Thunderbird to release 159.0 (64-bit), but the same thing happens in that version. I've done web and forum searches and have not seen any other reports of this. Any ideas as to why this is happening to me, or how I might fix it? (I've attached a redacted screen image showing what I see.)

Thunderbird has been receiving emails on my PC from Bell Sympatico for years, then suddenly stopped in July 2026 without my changing any settings, and I have to go to the Bell server instead.

All of a sudden I am getting a "connection to server wtrt.net timed out" message when trying to open my email. A David tried to help me: I went into the config editor and changed the 100 to 250, but it didn't work. The change didn't change back to 100 when I closed Thunderbird and reopened it. Anyway it is still timing out. Any help would be wonderful.

Thunderbird 158.1 – Outlook.com SMTP OAuth2 authentication failure

I am using Mozilla Thunderbird 158.1 (64-bit) on Windows 11.

I recently created a new Outlook.com email account, kim.bailey69@outlook.com, alongside my existing Hotmail and ntlworld.com accounts.

The problem

Thunderbird successfully receives emails from my new Outlook.com account using IMAP and OAuth2, but cannot send emails from it.

The error messages are:

"Login to server smtp-mail.outlook.com with username kim.bailey69@outlook.com failed."

"Sending of the message failed. Unable to authenticate to Outgoing server (SMTP) smtp-mail.outlook.com."

SMTP configuration

Server: smtp-mail.outlook.com

Port: 587

Connection security: STARTTLS

Authentication method: OAuth2

Username: kim.bailey69@outlook.com

Troubleshooting already completed

Verified all incoming and outgoing server settings.

Confirmed IMAP works and messages arrive successfully.

Confirmed sending from Outlook.com webmail works.

Confirmed my existing Hotmail account sends successfully through Thunderbird.

Tried smtp.office365.com as an alternative SMTP server, without success.

Created a completely new SMTP server entry and assigned it to the Outlook.com account. The same error occurred.

Deleted and recreated Thunderbird's saved Microsoft OAuth2 authentication token.

Checked Microsoft's authorised applications page. Thunderbird has explicit permission to send emails, and Microsoft confirms it was used today.

Checked Microsoft's recent account activity, which showed no unsuccessful sign-ins.

Verified with PowerShell that TCP connections to both SMTP servers on port 587 succeed.

Checked that cookies are enabled in Thunderbird.

Attempted SMTP diagnostic logging using MOZ_LOG with SMTP and SMTPClient modules, but the resulting log files remained empty.

When sending fails, Thunderbird immediately displays the authentication error without opening a new Microsoft sign-in window.

My question

Why does Thunderbird successfully authenticate to Outlook.com for incoming IMAP mail but fail SMTP OAuth2 authentication, despite Microsoft granting permission to send?

Is this a known Thunderbird issue, and what specific diagnostic or corrective action would you recommend that has not already been tried?

I would prefer to resolve this without deleting or recreating my existing email accounts, as they contain many years of messages.

最近、リリース版Thunderbird 157.0.1にアップデートしたら、今までの①アドレス帳、及び②送信メールデータが全部消えてしまった。その後、リリース版を削除して従来の通常版をバージョンを再インスト―ルしたが、今までの①アドレス帳、及び②送信メールデータは出てこない。ついては、この2つのデータを復元する方法を教えてください。 よろしくお願いします。

I hate when I receive an email with a calendar event attached. This event automatically imports into my Calendar. I dislike this. Now I am getting spam emails with calendar events attached that are importing into my calendar. With so many calendar events it's not obvious I have junk events.

How do I prevent Thunderbird from automatically importing calendar events. I mean, Thunderbird has no clue whether the event is wanted or not. In fact, when I delete an event automatically imported without my permission, an email is sent out saying I declined the event. This is just not reasonable.

Can I turn off this automation because it caused way more trouble than it's worth?

I have now the version 158.01 (64-bit) with Windows 11. My Gmail account only dowloads email like once a day. The server settings are: -Check for new messages at startup -Check for new messages every 10 minutes This started a few days ago, while I had the version 158.00. I have many accounts on Thunderbird, and re-installing all of them would be time consuming. Any suggestion?

Hello ,, i'm working in thunderbird and i use 3 PC's but it's not sync like if you add new account or delete an account send msg's draft etc.. i was looking for solution for that,, every one tell me you must do it manually take the the thunderbird folder and paste it to another PC's .. is there any way to make them sync togther ? thanks

My email on Thunderbird no longer loads on my laptop. It's fine on my desktop. It just stays a blank screen. "No message found" it says. I have to shut it down and when I do it says "Thunderbird is not responding." Can you give me a step-by-step on how to fix this?

I was bumped off Google and Thunderbird for some reason but my wife's account was left alone. eM was recommended by a friend but I much prefer to get back on T-bird, can you help? Thank you very much.

Boa noite

Solicito ajuda para configurar o Thunderbird no meu domínio agp.experience.com.br da superdominios

tento fazer as conexões e voltam com flaha no servidor

Tanto no desktop como no android

agradeço a ajuda

I can delete email one at a time, but I have some folders that have over 1,000 messages. With the election coming up, I have collected so much political email and I want it all gone. Unsubscribe seems to delete one and 5 more pop up! Thanks!

Currently my Thunderbird uses Virginmedia server. Virginmedia is getting out of the email business altogether and will delete all their email accounts in the near future. I would like to use Microsoft new Outlook as my replacement server. How do I make this change while keeping the same email address? (I suspect there will be thousands asking the same question)

All of a sudden I am getting the following message when I try to log into my email: Thunderbird connection to server mail.wtrt.net timed out. Why? How is this fixed?

I have several MBOX files with me and I want to import MBOX files into the Thunderbird email client. I've come across different methods, including manual techniques and third-party tools, but I'm unsure which approach is the most efficient, especially when dealing with multiple or large-sized MBOX files. Some methods also seem complicated for users who are not very technical.

Suggest me any reliable tool for this!

I have been setting up a PC with Thunderbird for my mother. I want to move her off a "Messaging Company" email to an Outlook email address. Currently I have 3 email accounts on her PC: - Messaging Company - Outlook - Gmail (loaded for testing and because she has an Android phone) Messaging Company and Gmail seem to behave just fine, both for sending and receiving. Outlook seems to work fine for receiving email. For sending, it works when I clear the credentials and set them up again. This only seems to last for a while, and it's as if Thunderbird forgets the SEND credentials. I'm not sure if this is after a reboot or some other cause. I have walked through all of the relevant advice on OAuth2, STARTTLS, etc. I don't think it is a configuration issue at this level because I can send for a while. It seems to be something to do with retaining the credentials. Any help would be appreciated - if I can't get this going, then I may have to move here to the Gmail account but I have my own reasons for wanting to use Outlook.

I cannot get Thunderbird to launch. It acts like it is stuck on perhaps one account and circles keep spinning as if it never can get a few of my tabbed emails open. It keeps saying it "isn't responding." Since this began happening a few days ago, I've stopped the Thunderbird task through Task Manager, I've shutdown and restarted my whole system multiple times, I've updated to the latest Windows platform and made sure my drivers were all up to date... I can't update my thunderbird (if required) because I can't get in in the first place. I have hundreds of emails in multiple accounts under my current Thunderbird. I can't afford to lose all that history. I don't know which version I'm using because, again, I can't get the desktop app to launch. What do I do?

When I launch Thunderbird via icon ( version 158), it always brings me to sign on page for Thundermail.. If Thundermail is by invitation only, how do I get back to the real TB page. I can access webmail, my account, and portal. I only see Version 156 in download folder and only have default-release and default in the profile. I have no clue then what is happening. Will bringing back an earlier version. "ABOUT" shows version 158 and nothing else.

Also, my android email & passwords have remained constant and I did not have to change anything.

Folks, this is a rather alarming setting. I’m not sure if this counts as a bug—if it is, please fix it; if not, please explain why. I’d like to know, as it might be reason enough for me to switch to a different email client. Thanks.