Thunderbird Community Forum

It is my custom to run spell check after typing an email. Today, sudenly, the write window hangs when I click on spelling. Does not happen in troubleshoot mode. I have no extensions installed and default theme. I did try disabling hardware acceleraton, but did not help.

Yesterday all workd OK, and thre have been no changes to the computer snce.

I keep getting emails like the one below. How can I stop Proofpoint from blocking emails like this? I can't get any response from Proofpoint.

Thank you.

Subject: Mail delivery failed: returning message to sender Date: Mon, 23 Mar 2026 15:32:49 -0400 From: Mail Delivery System <Mailer-Daemon@server240.web-hosting.com> To: [edited]@unexpectedwildliferefuge.org

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

[edited]@marshallsterling.com host mxb-00261401.gslb.pphosted.com [148.163.148.189] SMTP error from remote mail server after initial connection: 554 Blocked - see https://ipcheck.proofpoint.com/?ip=66.29.141.68

We have asked this before, and we still are not able to resolve it at all. Several items: We have two email addresses used by Thunderbird, for many years. [email1]@apaltd.com and [email2]@apaltd.com. Since the last "update", some many months back, her account has had TWO "sent" items/boxes, and they do not have the same items in them as "Sent". We tried to get rid of one, but to no avail. Also, the headings used to have features that showed "dates" in order and other normal things that we used all the time. Now these are gone and we have no idea how to get then back to way to the way opening page was originally, and we are seriously thinking about how to use another service, however we have been happy Thunderbird users for many, many years and need to return the site to its original layout. You folks have tried to help before, but none of the advice worked (i.e, right click on one of the sent boxes to remove it) We are reluctant to simply re-install Thunderbird lest we lose all our other data. We are at a standstill and need advice and help as soon as anyone can help. If any more information is needed, we will happily supply it. Thanking the community in advance for any help/solutions. Charles and Penny Kindt

Message sent has red texts (all containing an hyperlink). When vizualized in Thunderbird they all appear in blue. When vizualized in Gmail they appear in red! Texts written in red in Thunderbird messages still appear in black in draft's message!

I’ve tried all versions of Thunderbird on my 2020 M1 Mac, and even though I log in correctly, it doesn’t load emails from my account. I used to use Thunderbird normally because I needed it, but I haven’t used it for two months, and now I see that it doesn’t work when I try to connect to my email. It connects to my email normally, but the problem is that when I click on “Inbox,” there's nothing there, and when I click “Fetch Mail” to try loading it again, a message pops up at the bottom saying everything is fine, but in the end, I still don't have those emails. What kind of error is this?

Hello and thank you! When I print emails on our A4 (210x297mm) paper, to which the printer dialog is set, only the bottom half of the header, and top half of the footer, are printed, at the very edges of the paper. This doesn't 'feel' like a printer setting, but more of a Thunderbird setting, for if I set the paper size to US Letter, the footer prints 15mm from the bottom, but still only the top half of the text appears (truncated at the waist). Can you help?

Recently my email subfolders stopped being visible on my Thunderbird desktop. They are still visible and accessible on my Thuderbird Android app on my phone. Any suggested remedies I see call for steps that I don't seem to have in my settings. My desktop SW version shows as 148.0.1 (up to date)

My email was originally set up with Brighthouse which was acquired by Spectrum. My email address has a cfl.rr.com extension. Because of a hard disk problem, I had to reload Thunderbird. Spectrum is still maintaining the old Brighthouse accounts but support is extremely limited.

I can now get into my account in Spectrum's email and can send and receive email there. I had to use a password I set up for Spectrum to do that. But Thunderbird will not recognize my cfl.rr.com account. I can import that account into Outlook and Gmail, but not Thunderbird. It appears to me that Thunderbird is looking for a password that Outlook and Gmail don't require. If I had an old Thunderbird or cfl.rr.com password I have lost it.

I prefer Thunderbird, and I need to get my address book and history files back. I have just set up a new email account in Gmail and imported it into Thunderbird. Is there a way I can I recover my old address book and history files? I do have all the old Thunderbird files that I backed up before I had to reload Thunderbird.

I have been using Thunderbird with two POP3 Hotmail accounts for some time and I am trying to set up a third account with exactly the same configuration. However, both the automatic and the manual configurations failed. The new account receives mail, but the outgoing smtp server config seems to have a problem. Sending messages times out or keeps prompting for a new password.

The Hotmail account has POP3 and IMAP enabled. Thunderbird is set to receive all cookies. I cleared history and cache after every attempt and also temporarily disabled the firewall.

Any suggestions about what the problem could be?

Hi, I'm tring to rearrange the order of my email accounts in the left hand pane. The FAQ says sandwich icon -> account settings -> move them around in the desired order. This looks OK in the account settings list when I do that, but when I close it, the accounts order is as before, and this order shows up again when I re-open the account settings list. Is there any way to make this "stick"? Do I need to click some hidden Confirm button? Many thanks in advance!

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 have a lot of message filters that I've created over the years to filter out SPAM (as well as other more positive purposes like sorting mail to specific folders). I'd like to clean out the ones that are obsolete.

If I choose Tools > Message Filters, I get a display window on the screen with some of my message filters shown. But the reason it's "some" is that the top and bottom of the window are well off the screen display. I can double click on a Filter and edit its details and I can delete a filter by pressing the delete key. But I can't scroll through the list. Any filters that are out of range are not accessible.

Is this a bug I need to report? Or am I missing something?

Hello everyone. Thanks for all your support.

A few weeks ago I started noticing a pop up window was occurring every (approx) 5 minutes in Thunderbird suggesting that I run a compact to save 992MB. I assumed this would stop happening after a few weeks and a few updates from Mozilla, but the problem has remained, so I'm coming here to ask about it.

Context: I'm on Windows 11. I have multiple email accounts that my Thunderbird reaches out to. At least one of the accounts is retired so reaching out to its historical server fails.

Reproducing: For me to reproduce it, I run the compact. Quit Thunderbird. Start Thunderbird. It reports 992MB can be freed. I let it compact. The main inbox disappears and reappears. I wait a few seconds and restart Thunderbird. It again tells me that it can save 992MB by running a compact.

What I've tried: I've tried repair on the inbox folder of the account I'm typically in. That didn't help. I have many other folders across many accounts and not tried to repair any other folders. I've searched the Mozilla help system.

Logs: It seems to me that a compact is probably failing but I don't know where to look for evidence of the failure.

Hi,

I have three outlook.com email accounts configured. Two accounts open to show all subscribed folders. One account shows the account name only, but no folders.

Activity manager shows: "The current operation on 'Outbox' did not succeed. The mail server for account wasaga72@outlook.com responded: Command Error. 12"

Sometimes all folders show. Sometimes all folders show after a delay.

Tried: 1 deleting all .msf files. 2 removing and re-adding the account

My wife and I both have identical Laptops with the same three outlook.com accounts. Mine using version 148.0.1 (64-bit), hers using 140.8.0 esr (64-bit) both have the same problem.

Any help would be appreciated,

John

The University of Minnesota makes me change my password for their email IMAP server every year. I use Thunderbird as my email client. I have not had problems in the past, but this time Thunderbird does not connect with the UofM server and I cannot update Thunderbird with my new password. When Thunderbird tries to connect, I get a Google "help" message about clearing my Chrome cache that does nothing. I deleted the old IMAP password in Thunderbird, but that did no good. Is there a way to update my credentials within Thunderbird?

I m using Linux Thunderbird 140.8.0esr Some emails have long unwrapped lines, how can i force a wrap boundary? e.g always wrap at 80 chrs or better yet, wrap to fit the viewing window

I have been trying to add new email accounts to Thunderbird and they never complete the process (I have several that configured correctly prior to this error). I have tried both automated methods (With and without HUB) and the manual method of adding an account. Here is what is happening. When I add an account, I can watch Thunderbird login to the account on the status line. The login goes correctly, however the "Done" tab is always greyed out, the process never completes. I then try configure the account manually at the same screen and I get "the server is already in use" message. I believe that Thunderbird is not correctly closing the connection, leading to the "server is already in use" message, but I am not sure how to correct the issue.

I am currently unable to login into my Thunderbird account. My email provider (Internet Lightspeed) told me to go into Tools>Settings > Privacy & Security > Certificates > Manage Certificates. In the Certificate Manager, go to the Servers tab, click Add Exception, enter the server address which is imap.lightspeed.ca. I did that and got the following response: This site provides valid, verified identification. There is no need to add an exception.

The Certificate Manager/Servers window now shows imap.lightspeed.ca:443 as the Server. Lightspeed says that is correct and need to contact Mozilla Thunderbird. Thunderbird updates are current. Any suggestions? Patrick

When I send a mail with FileLink, I get the message: "The message could not be sent. An error occurred while sending the email. The server responded with: “Spam message rejected.” Please check the message and try again." (actually, in French: "L’envoi du message a échoué. Une erreur est survenue lors de l’envoi de l’e-mail. Le serveur a répondu : Spam message rejected. Veuillez vérifier le message et essayer à nouveau.")

I made different tests:

• change email source (so, change SMTP server): it worked - but I do not want to change the standard SMTP server of the initial email address
• after the first error, the attached file, which is a shortcut to the big file, can be suppressed, and not the link in the body of the message ; sending the message is accepted

So, I suspect the spam filter to refuse the "attached shortcut".

The question: Is there a way to configure the FileLink feature so that it does not attach a file, but just add the link the body of the message?' Or are there other neat workarounds?'