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Hello,

Im struggling with adding second email account in the freshly downloaded Thunderbird on new PC. I tested on multiple PCs and the errors keeps repeating. It says the login information are incorrect but I know for sure they are correct. Exchange auth error it says. After multiple login tries the app just freezes and stop responding.

The first email account added is working fine. Thunderbird version 144.0.1. Windows 11

I am on a MacBookPro running MacOS 15.5.

My FireFox automatically updated to 139.0.4 on June 10th. Since then, my ability to access the internet with FireFox only has been intermittent - I can connect for a variable number seconds and then it disconnects for minutes or hours. I have no problems connecting to the internet with Chrome or Safari, or with other applications. My perusal of the forums leads me to believe that it is the latest update that is causing the problems.

Has anyone experienced this problem and/or does anyone have a fix? Thanks in advance.

For the last day or so, Firefox is refusing to resolve any web pages. I have had to write this in Safari, so I can't share the data from Firefox. Sorry.

Please help, thank you :)

2017 iMac, OS 13.6.9, Firefox 140.0.4

Have used Thunderbird for years and 2 years ago, my Cox service eliminated supporting their own emails server and now Yahoo supports. I am having a problem over the past 2 weeks where I click on my Thunderbird app to load the program and get emails, and it times out after about a minute every time I try to log in. I have deleted the Thunderbird account and tried to add a new account, and it continues to time out every time.

What am I doing wrong?

Hi, perhaps my problem is not that unusual, but I'm finding it a bit difficult to solve. I have three email accounts on Thunderbird, and all of them have exactly the same specifications. They are all @hotmail.com. They have the same server name (outlook.office365.com), same port number, same connection security, same authentication method (0Auth2) and same Imap default release code. Never had a problem. Then on July 10th just one of them stopped opening and a message window appeared saying that authentication was OK but it wasn't able to connect. The other two continue to open as before. Any idea on how to rectify this, please.

Following a recent update to Thunderbird, I lost connectivity to my email server. Here is the message from Thunderbird - "The certificate for pop.scdconline.org is not valid for that server." The current version of Thunderbird on my Windows 11 PC is 141.0 (2025072114:12:26). It was installed on 7/22/25 at 2:18:53PM. The last email I received through Thunderbird was on 7/23/25 at 6:18PM (EDT). I can still access the email account using webmail. Prior to this issue, I have been using Thunderbird for this email account since the first of this year with no issues. I'm out of idea, any suggestions?

Hi, Long time Thunderbird user here. I've not experienced this issue before. I am having trouble configuring Thunderbird to correctly setup a new Outlook account. I get an error message "The current command did not succeed. The mail server for patsycrowly@outlook.com responded: User is authenticated but..." The rest of the error is cut off by Windows notifications. Not helpful. I'm still using Windows 10 (choice would be a fine thing) on a PC. I've spent hours trying all the suggestions re setup online both Mozilla and MS Outlook, I'm sure you know how numerous they are. I understand that imap and using oauth are the way to go, so have avoided POP. I have allowed cookies, I have tried among other suggestions the most recent: - https://support.mozilla.org/en-US/questions/1513917 and WavidDilly's response and solution 6/16/25, 2:20 AM. I have definitely checked that Thunderbird is enabled in Outlook and that both IMAP and POP are enabled. I've uninstalled and reinstalled the account (ensuring that relevant passwords were removed first (in case!)) an removed the data files before reinstallation etc. I am dreading that I may have to do the same with T'bird itself. BTW I am definitely using the latest version 144.0.1 (64-bit). I am a reasonably competent adult but sometimes find that the more recent versions of T'bird are not as intuitive as they once were; so please will you be kind and make your response very clear with simple instructions. Thank you in advance for your reply. Patsy P.S. Screen shots of settings attached.

I asked about this in the past but have got nowhere. I haven't been able to use my Thunderbird account since Last November. I keep getting the message "Connection to server imap.iowtelecom.net timed out" I can get emails through the providers email but can't get them through Thunderbird. I have used Thunderbird for many many years. I can't figure out how to correct the issue. Wondering if I should try setting up a completely new email address with it but have had the old one for many years. Any help is appreciated. thanks!

Hello, I have for a long time a mail "stefan.ch@aliceadsl.fr". I recently changed computer and wanted to add it in Outlook 2016. Failed. I tried to do the same with Thunderbird, after reading that I can recover/integrate a ".pst" file with my historical data from Outlook 2007 (the previous one) Failed. Messages saying that "cannot fond the server". Stephane

Good afternoon!

Thanks for the great customer!

We have several computers on a local network without internet access. There is a problem in Thunderbird 143 - files are downloading slowly. POP3 and IMAP are the same. From several tens of seconds to one and a half minutes, 11 files from the letter were downloaded, totaling 20 MB. There is such a feature - if you disconnect the network adapter, the problem practically disappears. There was no such problem in the Thunderbird 115 version. The Em client and Mailbird clients were also installed for the experiment - they also do not have such a problem.

The mailbox is small and contains 20-30 almost empty emails.

Tell me, please, what can be done about it?

Sincerely, Yaroslav.

本件はIMAPでMicrosoft365アカウントをサインインしようとしたときに発生している事象です。 最初のユーザー追加画面で氏名とメールアドレスを入力します。 その後、メールアカウントの種類を選択する画面でIMAPを選択して「続ける」をクリックしても「設定を検証できませんでした。ユーザー名とパスワードが正しい場合は、サーバー管理者があなたの選択した設定を無効化している可能性があります。別のプロトコルを選択してみてください。」と表示され追加ができません。 上記メールアカウント選択画面で「設定を編集」をクリックしても結果は同様ですが、「詳細設定」→「テスト」をクリックすると、「次のアカウント設定が、指定されたサーバーを調べることにより見つかりました: 」と表示はされます。 しかし、続けようとすると「受信サーバーの設定がすでに存在しています。」と表示されてしまいます。 なお、Exchangeを選択した場合は追加できます。 Microsoft365アカウントについてはIMAPを有効化していますのでアクセスがブロックされているわけではないと考えています。 解決策を教えてください。

When I try to set up one of my gmail account in Thunderbird on my new Windows 11 computer, It fails when attempting to authorize the connection. See the attached screenshot of the message I get when trying. I can go directly to gmail with my browser just fine.

I had this set up earlier on this computer, but it just stopped downloading mail, saying it could not connect. I finally just deleted the account a then tried to recreate it as a new account, when I ran into this problem.

Any thoughts?

I like the Firefox browser and Firefox was working fine for months but Firefox did ask me to do another update today. I did the update as requested and after the update Firefox will not connect to any websites on my desktop despite an excellent internet connection. I cannot find anyway to contact Firefox directly. For major problems such as a 100 percent failure rate to connect to any website, Firefox should provide direct help to the user as to the current major problem. I appreciate user ideas but Firefox should offer some help for major problems as the likely solutions can change over time. Hopefully if Firefox oversees user questions, someone at Firefox tech will at least respond to my question on this website or better yet contact me directly.

The problem may well be the update itself. The Firefox browser is working on my smartphone but not the desktop internet browser. I have some browser settings that I do not want to lose which a complete Firefox removal and reinstall would likely cause. Any suggestions from fellow Firefox users are appreciated and I look forward to them. Have other Firefox users experienced this major problem?

Thank you.

I upgraded to Thunderbird 140.0.1esr (64 bit) and 1 of the 4 email accounts has stopped syncing.

The one that stopped syncing is AT&T / Yahoo email via imap inbound and smtp outbound. It was working on the 128 release but as soon as I updated it stopped syncing.

I can still get email to/from the other 3 accounts, it still works on my phone and on my laptop with Thunderbird 128.12.0esr (32-bit) it is still working OK.

I have double checked account info and passwords and no issues that I can see.

My next thought is to downgrade back to 128 unless someone knows of a fix.