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Error msg:

Sending of the message failed. The message could not be sent because connecting to Outgoing server (SMTP) outbound failed. The server may be unavailable or is refusing SMTP connections. Please verify that your Outgoing server (SMTP) settings are correct and try again.

Attached screen shot.

Connection to pop.mail.yahoo.com times out and no emails are downloaded. A new windows appears from https://login.yahoo.com/ that I have never seen before asking for username and password but this returns a "something went wrong" error. Is there an update, or a setting change, that resolves this problem?

Thanks

Frank

HI, Thunderbird for Mac no longer allows me to see emails more than 4 months old. I have an AOL account and when I use the (lousy) AOL app I can see email going back at least a decade, so I know they are there.

This changed with a recent TBird update. I have checked online support, studied the different settings, and cannot find out how to set TBird to let me access all my email.

Can someone help me with this?

Thank you, James

Hi,

I have been trying to investigate why, in my Yahoo email logs I am getting logins from Virtual Gecko.

Until I started investigating this I had never heard of Virtual Gecko. I certainly have never installed it. The logins are coming from the same device as my web browser login to Yahoo, so it is something on my device, at least it is according to their logs.

The only software on my machine that logs into Yahoo is Thunderbird. And their logs have never shown those logins; but I do get emails about them. Is there any chance Yahoo! is mistaking Thunderbird for Virtual Gecko?

I tried closing Thunderbird and signing out the Virtual Gecko the connection from within Yahoo! and then signing into Thunderbird. That tests seems to indicate be causing an event in the currently logged in devices on Yahoo. At least not immediately.

Not that appears to be your problem but do you have any clues as to what is going on?

I will raise this with Yahoo! and if it follows my previous experience of their support, they will charge me for the privilege of not solving my problem.

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 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.

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.

Hi there.

For some reason, 3 of 4 accounts I use no longer open on the accounts list. I cannot expand them, I cannot "Get Messages" for them, there's no reaction whatsoever, as in no message in status bar (which works fine, as confirmed with that 1/4 account that still works).

I checked for subscribed folders and all of them are. I even was able to add a new folder, which does get added via IMAP. This is, therefore, not a connectivity issue.

I also checked the Developer Console and Activity Tasks, absolutely nothing shows there.

I removed global-messages-db.sqlite, folderTree.sjon, the .msf files. I checked in Troubleshoot mode. Nothing helps.

This looks like some nasty bug and I am happy to help debugging this further, if you point me in the right direction.

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)

I got a new account on my german provider 1&1 and used the right servers the company recommends on its Website (same servers as the previous account). For some reason it is not possible for me to send any Emails but to receive them. On my Iphone I neither receive nor send messages because the server isn‘t working as well. I tried several different accountnames…. I hope you can help me. Thank you!

(PS: first image from Iphone, second image Thunderbird on Macbook)

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.

Apparently MS has changed something in their OAuth2 and Thunderbird has yet to catch up. I've seen several other questions regarding this, but no workable solutions, just silly replies. Is TB actively working on a solution or am I now forced to install Outlook?

Unable to authenticate to Outgoing server (SMTP) . Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)'.

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?

Sent and received. Please notice the asterisks. Where do they come from? John

Message Sent: Fantasia I and II Georg Phillip Telemann 1681-1767 Kleine Passacaglia Michael Kuntz 1915-1992 Fair Phyllis I saw

Message Recieved:

*Fantasia I & II* Georg Philipp Telemann (1681–1767)
         Telemann’s Fantasias capture the brilliance and balance of the
         Baroque era—each movement a miniature world of counterpoint,
         grace, and invention.
*Kleine Passacaglia *Michael Kuntz (1915–1992)
          A modern take on a timeless form, Kuntz’s piece builds lyric beauty
          over a gently repeating bass figure. (See insert for more)
*Fair Phyllis I Saw* John Farmer (1570–1601)

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.

When I send an email from my account dezandcathy@optusnet.com.au, I receive a message "Your message was sent but a copy was not placed in your sent folder (sent mail) due to network or file access errors. You can retry or save the message locally to local folders/sent mail-dezandcathy@optusnet.com.au" This problem has only occurred within the past week. For some of my sent emails, I have retried sending the message and it has appeared in my sent email folder, but not for all the emails I have retried. Checking with the recipients, they confirm receipt of my emails even though they are not shown in my sent email file. Can you suggest a solution? Thank you Derek Maule