Thunderbird Community Forum

Hello community,

at my place of work no one can send or receive mail anmore using Thunderbird. The problem suddenly appeared last monday. No changes regarding the network or settings in Thunderbird happened prior to this.

Here's what I tried so far and things I can rule out:

• same problem appears on all devices (desktop and laptop PCs) in our office
• our work mail server is online and working, I can access everything using the webmail-interface in the office network
• new installation of Thunderbird without any profiles and fresh account confguration doesn't solve the problem
• I can connect to our mail provider and send and receive mail when using my home network or my personal phone hotspot
• I can connect to my private mail provider using Thunderbird while in the office network
• troubleshooting mode doesn't solve the issue
• renewing the internet connection on our router temporarily/once allowed some devices to receive mail
• pinging the mail server (mailserver.[workdomain].de, no specific port) via command line was successful while Thunderbird was unable to connect to the mail accounts

IMAP-Log returns the following error codes:

• D/IMAP URL failed with code 0x804b000e
• D/IMAP URL failed with code 0x804b001e

I would be glad if somebody could help me out. If you need any more details I'll provide them. Thanks in advance!

Today at around 10am my thunderbird email client has just completely stopped working.

I don't see any problems reported have tried swapping from WiFi to Data and no difference.

I have multiple accounts connected to the client and all of them are not working.

Is anyone else experiencing similar or had it happen?

I have a similar problem to others reporting a connection time-out. But the circumstances now seem different. It is getting worse. First thing today, I noticed that Thunderbird emails (current/up-to-date version) were taking several minutes to finish sending. After sending 3 successfully, but slowly, all further emails failed, as per image attached. My wife's computer, using the same email provider, etc, was working okay. I checked and compared the account setting, and they were slightly different (no idea why) so I altered mine to match the other PC. That didn't make any difference anyway. Then (a few hours later) my wife's PC started having the same problems as mine, as if it's a spreading disease. Could it be a virus? Thanks.

It was working fine on the new computer until yesterday. Now I get a pop-up box that says: ' Unable to connect The connection was refused when attempting to contact localhost.

The site could be temporarily unavailable or too busy. Try again in a few moments.

If you are unable to load any pages, check your computer's network connection. If your computer or network is protected by a firewall or proxy, make sure Thunderbird is permitted to access the web.

Each time I attempt to login w/ T-Bird, google mail gives me this message:

400. That’s an error.

The server cannot process the request because it is malformed. It should not be retried. That’s all we know.

Please see attached image of the problem.

I have tried looking on Google for ideas but have not found anything on this or how to fix. Hope someone can please help would be amazing!

Google -

400. That's an error

The server cannot process the request because it is malformed. It should be retied. That's all we know.

Considering migrating from Outlook to Thunderbird (TB), as it is a logical potential path. Best I can tell from AI input is placing my message store on a network share (colocated, stable network), would likely be unreliable. Said that TB storage format was basically fragile and subject to corruption if there was any kind of hiccup in the data transfer or if something happened during a power outage for example. Wanted to see how the real community felt about that and if it was indeed inadvisable to do so.

Thunderbird functions normally (sends/receives), except after Windows 11 goes to sleep, I log back in without difficulty., but attempting to use Thunderbird to send email fails with the message

"Sending of the message failed. The message could not be sent because connecting to Outgoing server (SMTP) smtp.mail.me.com failed. The server may be unavailable or is refusing SMTP connections. "

There's no prompt to re-enter the primary password, and the only way to restore normal Thunderbird operation is by rebooting WIN 11. Is this a known bug with a workaround? The failure occurs whether the outgoing server is smtp.mail.me.com (Apple), smtp.comcast.net, or smtp.gmail.com

Today i moved mails between folders. The move was successful, as confirmed by the webmailer. However Thunderbird stopped displaying these messages. Instead i got several popups, that the server is not available.

I have 2 issues with that:

First: Popups are disruptive. Especially when they block interaction with Thunderbird. Especially when using a tiling windowmanager(sway). Especially when there are multiple, which need to be closed in a specific order, because interaction is blocked by the newer popups.

How can i block these popups? Disable sync is not a reasonable option.

Second: Why did thunderbird not display the moved messages? Is it a bug? Or a config issue?

Every time I open thunderbird I get a blank screen with this message, 'Edge: Too many requests' over the top of the thunderbird screen. This screen stays on my desktop after I close Thunderbird and I have to change my screen resolution in order to close the screen. Can you help please? Martyn Smith

I have been using Thunderbird for many years. I have 4 accounts that have all been set up and working fine. This morning the 2 yahoo.com accounts stopped working. I logged in to the impacted accounts using a web browser and password just fine. I then updated Thunderbird to 116.0 to see if that would fix the problem, but it did not. The outlook and gmail accounts are working fine, for now.

When Thunderbird attempts to download mail for the yahoo accounts, I get a large pop-up window with "Edge: Too Many Requests". The pop-up window is blank except for that error message. I get the small pop-up with the Authentication Failure message. Sometimes I get Retry, Enter Password or Cancel. But I never see a window that will allow me to enter my password.

I can send/receive mail from the accounts while logged in via a browser but authentication fails within Thunderbird.

I use Thunderbird when Postbox acquired another. I am using 2 computers - desktop, old (10+ years), still Windows 10, and 2 two emails; new laptop (traveling), Windows 11. I download Thunderbird and set up my accounts - gmail.com and twc.com. Troubles with gmail.com, but finally I set up. However, I can't set up twc.com. I like twc.com-- no reason. (Time Warner Cable (twc) bought Spectrum. ) I can login twc.com webmail. Not Thunderbird. I looked carefully set up, Thunderbird searched, found "Host: mobile.charter.net" (Huh?, , continue, enter my password - "Error: ---". I removed VPN Windows 11, no difference. (Curios, my laptop and Firefox, my bank rejected connection. My desktop and Firefox still connects! I dread the day must update.)

I am look forward yours reply. (Maybe Spectrum is searching to dump twc.com.) Jeremy Fields P.S. I wrote with my desktop - windows 10 -, my new laptop (windows 11) is problems

The system was working fine. The next day, when starting Thunderbird (TB, the status line shows logging in to server but loops; no errors or messages, Thunderbird is 'locked out' spinning. I see the normal INBOX page, but logging in never completes. NO CHANGES were made to TB accounts or settings. I have re-installed TB, re-booted, but no change. I cannot check/change any of the accounts or do any further 'debugging' because TB is spinning. The server login is fine because Webmail can be used. Internet connection is fine, because browser works. 1. How can I stop TB from trying to login at start up? 2. What could/would cause this behaviour?

Any suggestions much appreciated.

Proszę o pomoc. W pracy na wifi program nie chce mi się połączyć z serwerem poczty. Jeśli połączę komputer z inną siecią wifi nie ma pproblemu program łączy się z serwerem poczty i bez problemu pobiera i wysyła pocztę

Hi, When i start the TB-client on a win10 desctop there will be an Authentication error connecting to server imap.gmail.com.

from Google: 400. An error has occurred, The server cannot process the request because its format is incorrect. The request should not be made again. Unfortunately, we don't know more than that!

It still seems like the email arrives to the gmail account. But it turns out that the email doesn't always arrive via sync. Do you see any problems with the TB and gmail connection?

For the moment I don't know the Thunderbird version, I will be back.

TIA, /Leo

Hello, since 2 weeks the IMAP settings don't work. I didn't change anything with the accounts. Regularly I had to update the settings on my android version and it works well. But on my windows version ou on my linux version it doesn't work. I enter different name (the surname only, user name, or the mail address or name and surname). I tried all the options but it didin't word. I stopped trying last week on Thursday and tried again friday afternoon. I tried again several options and it works until saturday. Again I didn't change anything. I receive the notifications (in french) : "can't access the server outlook.office365.com" for the accounts. It was on my windows version AND on my linux version. I really don't know how I can fix it. I cleared the cache several times. Verified the server names. Today I serched for the settings on outlook for the IMAP server but didn't find how to change or disable it (the option were not visible on the setting page). I deleted the accounts to add them later but when the windows popup open even if I enter my password, and the code (if necessary) thunderbird send a message like "error. verify the id, username, address or password". I tried with the new thunderbird version on windows (because mine was old) - didn't work either. I don't know what to do or try now.

I have the android version and it works well, but this is on a secondary device and I absolutely need my mails on my main device and I really love using thunderbird. I even installed it on my kids devices. I really don't want to install another email client.... and absolutely not outlook T-T.... My thunderbird on linux is updated and didn't work too. But it's on my main device too, so if you can help me make it work on linux, I'll be happy ^-^.

I thought it was a connexion problem but even when I change it, it didn't work (on windows or linux).

Please can you help me fix this problem ?

Edit : Just wanted to add that the version on Linux (Mint) is the 140.12.0esr

I have four different email accounts. A week ago, all incoming and outgoing traffic suddenly stopped . Webmail works normally. I have no viruses, trojans, etc. I deleted one of the accounts and tried reinstalling it. I can't do it anymore. The system keeps responding: "Unable to authenticate to the server. Username or password configuration may be incorrect." But they are all abolutely correct. I don't know what else to do. Any clue? Thanks

[Edit:] I'm using Kubuntu with Thunderbird installed via flatpak using the flathub repo.

When attempting to add my calendars on our Nextcloud server, I can't get further then the second dialog.

Steps to reproduce: 1. New account > Calendar 2. Select "On the network" 3. Enter the correct user name and address (I did try the server address AND both CalDAV addresses presented in the calendar settings on the Nextcloud web app). 4. Press "Search for calendars" 5. After an extended period of time a dialog with a title "Adding a security exception" appears, claiming, that our Nextcloud site does not have a correct certificate (it does).

This is where the journey ends. If you add an exception, the dialog disappears and you are still at number 3. Trying again will produce the same result. Funny thing is, that you can press the button "Load certificate" in the "exception dialog" and then the same dialog will declare that our site does indeed have a correct certificate! But it will only allow you to close the dialog and you are still at number 3 and without any chance to add your calendars.

This is a completely new installation of Thunderbird. There are other folks that are using Thunderbird with their calendars on the same Nextcloud server and everything works happily. I presume this is a bug with the newer version of Thunderbird or something of that sort.