Thunderbird Community Forum

This is probably not a T-bird question, per se, but it is so strange it seems that this might be the best place to start, hoping someone might have some insight.

My wife and I each have our own laptops, running Win-11 Pro. Each laptop has T-bird 153.2.0esr (32-bit). We each have an account to yahoo mail (the site now hosting our Comcast email accounts). No problems since ... forever. Until today.

Now, beginning today, on my wife's laptop, when she opens T-bird, she gets a pop-up logon page, pre-loaded with her userid/email address. No input field for a password, but that it not unusual, as a lot of sites put that on a follow-up. But when we click 'next', it just rejects it. We were able to log into the yahoo mail web page (in Firefox) just fine.

After a lot of head scratching, I added her account to the T-bird configuration on my laptop. First time up, it prompted for credentials, but here it accepted them. So now we have her yahoo/comcast account configured and working just fine on my laptop, but continue to get credentials rejected running the same config on hers. Again, this has been working just fine up until today.

(If you are wondering about the connection between Comcast and Yahoo, several years ago we 'cut the cable' with Comcast, after confirming they would continue to support our email accounts. Then some time ago, they off-loaded that to Yahoo, such that we were able to retain our Comcast email address, but it redirected to and is hosted on Yahoo.)

Thunderbird version number: 148.0.1 Mail provider: Yahoo Client OS: Windows 10

The issue and steps I tried to resolve: On 1 Jan 2026 I switched from Outlook client on my Windows 10 PC to Thunderbird 146.0.1. I did not import any user data from Outlook but started with a clean install of TB for the new year. I use yahoo.com with POP3 as my email provider. Server Settings: Server Name "pop.mail.yahoo.com", port 995, SSL/TLS, OAuth2 Outgoing Server: Server Name "smtp.mail.yahoo.com", port 465, SSL/TLS, OAuth2

it all worked fine and I was very happy with the setup. Then from early to mid-February I was unable to use my computer. When I finally accessed Thunderbird again, it connected to Yahoo and showed that approximately 800 email messages would be downloaded and started downloading them. After downloading about 100 messages, Thunderbird timed out and I haven't been able to get it to work since.

I have read and followed or tried to follow these articles plus others that I may have forgotten about (not listed in any particular order) - OAuth2 Authentication for Yahoo, AOL and ATT | Thunderbird Help - including all the steps in Please check the following before asking for support - POP access settings and instructions for Yahoo Mail | Yahoo Help - Automatic Account Configuration | Thunderbird Help - Manual Account Configuration | Thunderbird Help - Thunderbird and Yahoo | Thunderbird Help - Send and receive messages in Thunderbird | Thunderbird Help - Can no longer get emails | Thunderbird Support Forum | Mozilla Support - Emails suddenly stopped downloading to Thunderbird 140.2.1esr | Thunderbird Support Forum - Get Messages | Thunderbird Support Forum | Mozilla Support - Cannot receive messages | Thunderbird Help - Problem with Thunderbird working with Yahoo Mail acccounts. | Thunderbird Support Forum

I have removed all messages from the Yahoo inbox and tried to find one or more messages that may be affecting the download. I don't know the best way to determine that.

I use Windows Defender for my antivirus. I don't see anything in Defender that blocks or scans email messages which would prevent downloads, although I could be wrong about that. if this might be the issue, please provide some guidance about how to check Defender.

I have uninstalled and re-installed Thunderbird. In the process I downloaded the setup file for Thunderbird Setup 148.0 and installed that version. It later auto-updated to 148.0.1. Before installation, I removed all external connections from my Yahoo account and completely removed Thunderbird from my PC, including the profile and profile.ini. When I reinstall and switch the account to POP3, Thunderbird captures the App password from Yahoo and connects just fine. But it still times out while attempting the first download of a message. The first several times it timed out, an error message was displayed but now it doesn't show anything. Except no messages are downloaded.

At this point, I don't know what else to try. Since I don't have much experience with Thunderbird, I don't know how to troubleshoot the process (logs to look at, etc.). I don't want to go back to Outlook but I need the email client to work and download messages. Any help would be much appreciated.

I've been a Thunderbird user for years without problem. However, since May 22, three specific messages continually reappear after deleting them from my Inbox.

I keep my Inbox empty and it stays that way, except for these 3 messages. Removing them from the Trash folder has not solved the problem.

My email provider is netaddress.com via POP3 account. I signed on to look at my inbox on their site via a browser, and the messages aren't there.

I have tried repairing and compacting the inbox, but the messages continue t reappear.

Do you have any other suggestions?

TIA.

ChuckM

Q.1. As the smtp server setting is "normal password" (screenshot 1), and I am entering my "normal" gmail password, why is it being rejected (screenshot 3)?

Q2. Why am I being asked for a "new password" (screenshot 2)?

Hi!

Trying to add new account on latest Thunderbird instillation, added information/configuration what I use on another computer and in the end it says: Component returned failure code: 0x804b000a (NS_ERROR_MALFORMED_URI) [nslOService.newURI]

Checked 10x for typing errors and it says same error. These account settings works great on previous versions wihtout Account Hub

How can I solve this?

Best regards,

Thunderbird keeps bringing in emails automatically. I don't want it to download anything until I ask it to. This just started when i had to reinstall Tbird after it stopped working for me. 1. It downloads emails automatically 2. I only want emails upon my specific request. 3. I can no longer find any switch to allow me to turn of auto downloads.

As of September 3, 2026 all my new emails are going into a random folder instead of the inbox. This is also happening on my wife's PC plus and we are not getting the emails to our iPhones until we get out of Thunderbird. What has changed? This has not happened before.

Sending of the message failed. An error occurred while sending mail. The mail server responded: <anonymous@[10.0.0.31]>: Sender address rejected: not owned by user a1.914306843. Please check the message recipient "christine.krieger@a1.net" and try again.

why do I get this on new download

Outlook.jpの個人アカウントをThunderbirdで使用しています。 IMAPは outlook.office365.com / 993 / SSL/TLS / OAuth2 で正常に受信できます。

SMTPは smtp-mail.outlook.com / 587 / STARTTLS / OAuth2 で送信すると、 535 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. と返されます。

smtp.office365.com / 587 / STARTTLS / OAuth2 も試しましたが、こちらは接続タイムアウトになりました。 MicrosoftアカウントのOAuth2認証と2段階認証は完了しています。 Outlook Web版・新しいOutlookでは送受信正常です。 Microsoftサポートには問い合わせましたが、Thunderbird側へ確認するよう案内されました。

この状態でThunderbird側にまだ確認すべき設定がありますか？ それともMicrosoft側でSMTP AUTHが無効になっている状態でしょうか？

All of the incoming messages are going to Trash. This includes messages I have not indicated as trash. I get no new messages to my inbox. Started today, 09/04/2026.

After your upgrade I was unable to send messages. The incoming I was able to fix but the outgoing I could not fix. I have included the email message sent to me and I have included a picture of the outgoing STMP,

In the last couple of days I’ve had a couple of alerts from TB when in other apps, seemingly random times, but possibly when I get an email (from memory, about Thunderbird requiring access to my Google account). I haven’t received any emails for a couple of days and I can’t send them (connection to Outgoing server smtp.gmail.com timed out). But, in TB account settings an outgoing server test was successful (Successfully established a secure connection to smtp.gmail.com:465). I also can’t pause calendar reminders, whatever I do they stay on the screen (but I can delete them with the X in the top-right corner). I haven’t changed anything in my TB or Google account settings. I’ve checked authorisations in my google account and TB auth is there. On my (android) phone, I can send and receive emails OK. OS Name: Ubuntu 24.04.4 LTS OS Build: (null) OS Type: 64-bit GNOME Version: 46 Windowing System: Wayland Kernel Version: Linux 7.0.0-30-generic

Could somebody please tell me what settings I did not make ....

I have four gmail accounts, say A, B, C and D. A is the default.

If I send a message from B to an outside email address, the reply routing is returned to the A address and not the B sending address.

If I send a message from B to C then the message is not received anywhere, it simply disappears.

If I open a browser and send a message from B to C then the message is delivered. So I know that the problem is with Thunderbird and not the email service.

Please tell me what I need to change in the settings ....

Hello All, all of a sudden I cannot send emails anymore. I do receive emails though. I have 4 accounts and none works. I went to account settings > outgoing ... all my accounts are set to SSL/TLS and below OAuth2. What goes into the Username field ... the email address or just my name? When I send a test email to myself the send window keeps going and going .. never sends BTW ... in Server Settings I have the same Authentication and Security as in Outgoing. Please help - I'm not getting anywhere. Also ... what goes into "Manage Identities"? ... just the specific email? or all four?

Thanks

I have Thunderbird 154.0 (64-bit) on Windows 11. When I opened Thunderbird this morning, it originally gave a message that the connection to the email server had failed. Before I had time to look into this, it downloaded a number of emails without headings and sometimes without text. However, Thunderbird on my Android phone, I discovered subsequently, had downloaded all the messages correctly. The problem seems to have now corrected itself for subsequent emails, but is there some way I can force the download of these previous incomplete emails? Also, this is a very recent update to Thunderbird - I think it was installed in the last few days. Is it a problem with the update and is it likely to occur again?