Diễn đàn hỗ trợ Thunderbird

I've successfully connected to a hosted Exchange server through EWS and NTLM authentication (kudos BTW). But there is a problem - often during operations against EWS I'm presented with "Login to account XXX failed" "Login to server YYY with account XXX failed". I can ignore it (cancel) and it will work for seconds or minutes but eventually reappear. Sometimes it's very frequent, sometimes is here and there. TL;DR; connection works, I can read directories and e-mails.

From looking at development tools I see these scenarios: 1. POST requests return 200 always (no messsage of course) 2. Eventually a POST would return 401. Then Thunderbird issues a GET, it returns 401 as well but response includes header WWW-Authenticate: NTLM XXXXXX. Then another GET is issued containing header "Authorization" with the value from previous response. This time it gets 200 and continues without POST requests without a dialog. 3. Sometimes there are more POST requests with 401 (I assume in parallel) before a GET is issued and then I see a dialog. Sometimes it recovers (regardless of whether I cancel or retry), sometimes gets stuck with 401 with dialog reappearing each time it tries something. This case it's similar in sense that thunderbird issues GET with 401 and WWW-Authenticate header, issues another GET with Authenticate header but still gets 401.

If I had to guess I'd say the problem happens when POST requests are issued in parallel, not sequentially. OTOH it might be a problem at the server, but it isn't very likely.

Trying to send 3 different emails. Hit send and get: 1) Your message was sent but a copy was not placed in your sent folder (Sent) due to network or file access errors. 2) Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.gmail.com timed out. 3) Your draft message was not copied to your drafts folder (Drafts) due to network or file access errors. How can I get these problems fixed?

Whenever I start Thunderbird, I get multiple (2 or 3) connection reset errors for random CalDAV calendars. When I sync the calendars, there are no errors reported and the exclamation mark on the effected calendars goes away and 153 and they are refreshed.

How can I solve this?

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.

I am getting the error "connection timed out to connect to SMTP server". I am running on Linux Mint. The same setting do work on MacOS so there is no wrong config or broken SMTP server. It was working well since a couple of years. I also tried troubleshooting mode but still the same.

Cheers, Thomas

For the last year or so, and not consistently, Thunderbird will not bring in new imap messages across multiple accounts. Sometimes closing and reopening will make new messages appear. If I close Thunderbird from task manager and reopen it always brings in new messages. When it does start working it will keep working for 1-3 days. Restarting my computer seems to make it work for longer. Running Win 11 Pro, but have the same issue on a Win 10 Pro computer, different antivirus on each computer. Seems to be the same issue as this post https://www.reddit.com/r/Thunderbird/comments/1gxduxt/thunderbird_not_showing_new_messages_unless_i/

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!

Error code: PR_CONNECT_RESET_ERROR

   The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
   Please contact the website owners to inform them of this problem.

Afterward no mail is being received from any of the providers, everything is stopped at last time I connected before the error, i.e. 7/9/2026

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.

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