Forum communautaire Thunderbird

I think I've tried everything to figure out why Thunderbird will not send emails.

Yes there was an update the last week of May to version 140.11.1esr (64-bit).

Yes the incoming and outgoing mail server info gibes with my ISP (Shaw) - added pix

Yes have done the necessary adjustments to Windows Defender and Firewall.

Yes I have increased mail.news.tcptimeout because occasionally have received message that "Outgoing server

• SMTP" mail.shaw.ca timed out. Try again. Yes I have indeed tried again.

Yes I have called Shaw and they will not offer any suggestions because TB is a third-party.

What's left to try? A version reversion? Thunderbird has been so stable for so long. I even considered Betterbird but it uses the same profile so............

Thanks.

My email account has been showing up in duplicate and I have lost my send emails Would be please to speak to someone to clear up issues [edited phone# from community support forum]

Thunderbird 148+ on Windows 11 repeatedly prompts for the password when synchronizing an Exchange account (professional) configured with the native Exchange support (no add-on installed).

The account only offers “NTLM” or “Normal password” authentication methods. OAuth2 is not available in the account settings.

During synchronization, Thunderbird asks for the password separately for many folders. However, clicking “Retry” usually works immediately without changing the password, and manually re-entering the same password also works.

The issue then reappears for the next folder, causing continuous authentication prompts (I have many folders...).

Actions already tested:

• deleting saved passwords and tokens,
• deleting/renaming key4.db and logins.json,
• restarting Thunderbird,
• recreating the account.

The problem persists.

This looks like an authentication/session handling issue rather than an actual invalid password.

Some mail in my spam folder is marked with the red flame spam icon, and some isn't. It's all spam -- that part is okay. Thunderbird has sorted everything correctly. But why wouldn't everything in the spam folder be marked as spam?

Hello, I have six calendars: five are hosted by one provider, Runbox.com, via SabreDAV, and one is hosted by a different provider, Apple iCloud Calendar. I am periodically seeing the error shown below on multiple calendars during automatic sync.

I have saved a two-day event history from the error console and can provide it on request, along with any other troubleshooting information that may be helpful.

I am technical by nature, but my programming experience was primarily with mainframes rather than personal computers. Could someone kindly help me troubleshoot this ongoing issue?

Thanks in advance.

Bill

10:34:53.958 An error occurred when writing to the calendar House! Please see below for more information. Error code: MODIFICATION_FAILED. Description: If you’re seeing this message after snoozing or dismissing a reminder and this is for a calendar you do not want to add or edit events for, you can mark this calendar as read-only to avoid such experience in future. To do so, get to the calendar properties by right-clicking on this calendar in the list in the calendar or task view. CalCalendarManager.sys.mjs:949:15

   announceError resource:///modules/CalCalendarManager.sys.mjs:949
   onError resource:///modules/CalCalendarManager.sys.mjs:803
   notify resource:///modules/calendar/utils/calDataUtils.sys.mjs:46
   notify resource:///modules/calendar/utils/calDataUtils.sys.mjs:73
   onError resource:///modules/CalCachedCalendar.sys.mjs:95
   notify resource:///modules/calendar/utils/calDataUtils.sys.mjs:46
   notify resource:///modules/calendar/utils/calDataUtils.sys.mjs:73
   notifyError resource:///modules/calendar/utils/calProviderUtils.sys.mjs:689
   notifyOperationComplete resource:///modules/calendar/utils/calProviderUtils.sys.mjs:662
   notifyListener resource:///modules/CalDavCalendar.sys.mjs:720
   doModifyItem resource:///modules/CalDavCalendar.sys.mjs:794

Here is an additional group of errors from the night before:

23:09:52.245 [calCachedCalendar] replay action failed: <unknown>, uri=https://dav.runbox.com/calendars/908506/bill/, result=2147500037, operation=[xpconnect wrapped calIOperation] 23:09:52.249 calendar: CalDAV: No response status doing webdav sync for calendar House CalDavRequestHandlers.sys.mjs:476:16 23:09:52.249 calendar: CalDAV: No response status doing webdav sync for calendar House CalDavRequestHandlers.sys.mjs:495:16 23:09:52.249 calendar: CalDAV: Error doing webdav sync: undefined CalDavRequestHandlers.sys.mjs:528:16 23:09:52.263 calendar: There has been an error reading data for calendar: House. However, this error is believed to be minor, so the program will attempt to continue. Error code: DAV_REPORT_ERROR. Description: There has been an error reading data for calendar: https://p31-caldav.icloud.com/204954917/calendars/home/. It has been disabled until it is safe to use it. CalCalendarManager.sys.mjs:952:16 23:09:52.263 calendar: There has been an error reading data for calendar: House. However, this error is believed to be minor, so the program will attempt to continue. Error code: READ_FAILED. Description: CalCalendarManager.sys.mjs:952:16 23:09:52.263 [calCachedCalendar] replay action failed: <unknown>, uri=https://p31-caldav.icloud.com/204954917/calendars/home/, result=2147500037, operation=[xpconnect wrapped calIOperation]

I accidentally deleted a good number of my emails from my local Pop3 server account. I don't delete my emails from my gmail server so I can just redownload all my emails but cannot remember the prefix needed to do it.

If I recall correctly I go under settings for my email account, then go to server settings and add the prefix to my email shown in the Username field under the Pop Mail Server Section.

Can anyone remind me of the prefix?

It was like restore:[my email] or all:[my email].

I should have made a note of it as I cannot find it anywhere online now.

thunderbird refuses to connect with my email account. it says, either the name is wrong or the passwort, or the settings. name and pssword is proofed, so its the settings. where can i find them, and what is to do ?

I added a new mail account and then after a week or so decided to remove it. But after removing it I kept getting a popup nag to enter a password for the removed account.

I have been using Thunderbird for years with no problems. However recently, Thunderbird very often simply stops responding. Sometimes it just hangs up and sometimes the program bar at the top displays "Mozilla Thunderbird (Not Responding)". If I try to wait for it to respond, it literally hangs for several minutes before it begins to respond again, and often, it simply never starts responding again. It has simply gotten to the point where Thunderbird is practically unusable. All my other application software continues to work with no problems. It's just Thumderbird.

The version number in this submission may not be correct. I can't provide the real version number because of the hangups.

Any suggestions?

Hello, My Provider is vodafone. Since you updated Thunderbird, i can't send emails. This Problem exist since about 2 Month. Vodafone cant help me, because they said, it is your Problem. I need very quick help. I need emails for my business. Thanks

Thunderbird is very glitchy and slow after the latest update - Thunderbird 140.11.1esr (20260522210329)

Especially, when I get a new email, Thunderbird stops responding for 5-10 seconds and then starts working.

I am using Windows 11

I've been seeing a doubling of *some* incoming messages, where a duplicate message comes very soon after the first one. For example, two incoming messages were received at:

Sun, 07 Jun 2026 14:03:10 +0000

Sun, 07 Jun 2026 14:04:31 +0000

So the second message came in about 1 minute and 21 seconds after the first, and not because of anything I did (as far as I know). But then that was it, no third message came in.

This isn't really a bug, as nothing is harmed, just a repeated message. Any thoughts would be appreciated.

When I highlight multiple messages for deletion; it can take up to a minute to respond; when I am working with gmail or proton, the deletion is immediate. When I am accessing Reagan with browser, the multiple deletions are also immediate. Appears to definitely be a handoff issue. Suggestions? I use Thunderbird on 2 win11 os and 2 linix mint 2.1 machines. I only delete and store to local on one machine (win11) ver/build 23H2: 22631.6199.

the default font for writing texts is too small for me to easily read. Yet when I send the message the text size too large, How do I control these font sizes independently

I was recently forced to change my gmail password. All of the help messages I found tell me that after I change my email password I have to save the new password to Thunderbird and I don't know where to save it.

I've been using Thunderbird on Windows 10 since last year sometime. Currently I'm on version 151.0.1.

I've 4 x mailboxes here and since yesterday, 3 of them show me an unusual message when checking for emails. I tried attaching a screenshot but although the screenshot uploaded, I couldn't find a way to insert it here. But the message says Unable to write the email to the mailbox and asks me to check if I've write privileges (which I have) and to cheek the available disk space.(currently 101GB free).

The message is happening 2 or 3 times each day and lasts for about half an hour, then everything works fine again. Has anyone else seen this??

i manage 8 email accounts for different projects I run.

When I open thunderbird, all my folders in each email open up. Is there not a setting to say don't open folders?

Have been successfully running Thunderbird for many years on Windows 10 on 2 different private computers. Within the last week both computers unable to send and receive messagees. BT E mail account is absolutely fine as can access it via webmail and via Android e mail app on my phone. Login details have not been changed. Have tried updating to 150.1 no joy. When trying to send a message we receive Send Message Error immediately but with no explanation as per attached image.