Thunderbird Community Forum

I have a POP3 account which will not download new emails. The indication is there are no new emails. I can access the email account through gmail and there are many new emails. I have checked password. I have gone through the re-indexing procedure and all other possible solutions I could find. I did find some information about Java and incidentally, there was a Java update on the day my emails began to fail, 8-16-2026. I found this error message, but I don't know how or if I can fix this: module is not a constructor ExtensionCommon.sys.mjs:1679:15

   asyncGetAPI resource://gre/modules/ExtensionCommon.sys.mjs:1679
   AsyncFunctionNext self-hosted:780

Thank you for any help you might provide. Please email to [redacted email from community support forum]

Bonjour, La langue FRENCH est cochée dans mes paramètres et pourtant à chaque ouverture de la boite mail, tout est en anglais ! Je veux uniquement la langue FRENCH.

Merci

Hi All,

I am on the latest release 156.0 on Windows 10. I have 3 email accounts, 2 gmail and 1 yahoo. The Yahoo account has been giving me problems since the last 2 weeks. Mind that yesterday I have a completely new Windows 10 installation so also TB installation is new.

I have renewed the Oath login, all messages were downloaded without a problem, but once in a while I get different notifications about server errors such as the ones below. There's also a third type of message error but haven't been able to get a screenshot of it.

Could someone please help me to solve this issue? I really don't understand why the problem is intermittent. Thanks in advance!

Having issues sending e-mails due to message: "e-mail not sent. Cannot connect to SMTP server 47.43.26.4 (47.43.26.4:587) connect error 10060" Requires 2-6 attempts to send. Also, problems with sending attached files, claiming to be too large.

I’m trying to understand how Thunderbird handles links to online media when an email contains a link to a photo or video rather than a normal attachment.

For example, if an email contains a link to public Instagram media, I may open it in the browser and use a browser-based option such as Indown.mobi to work with the media. Is there any Thunderbird setting that affects how these external media links are opened or handled?

I’m mainly interested in understanding whether Thunderbird treats these differently from normal attachments and whether there is a recommended workflow for managing them.

Hi Today, several emails that I have received, which I think were sent from an Outlook account, have, instead of what I would expect to see as the sender's address under correspondents, have Microsoft account team <account-security-noreply@accountprotection.microsoft.com> When I click on the email, I can see the genuine sender's address This has only happened today At least one of the emails that I received came from someone that I know uses Outlook Any ideas? Thanks

hello, i set up my microsoft 365 / outlook account in thunderbid using oauth2 and smtp (port 587, starttls). however outgoing emails fail to send. how can i resolve this smtp issue

I was attempting to move my thunderbird folders from one computer to a new one. I followed the instructions, copied the thunderbird app data and went to transfer it. However, two problems arose. First, it only held my incoming mail, not sent, drafts, anything else. Second and worse, those folders are now gone from my existing thunderbird on my current computer. How can I recover these and transfer them? I really need this info. I tried following the instructions from the troubleshooting menu, but that only showed me the folders which had transferred, not the ones that are missing.

Dobry wieczór

Brak strzałki do przewijania w dół w oknie kalendarza.

Proszę o dodanie strzałki do przewijania w dół.

Z góry dziękuję i pozdrawiam Mooner

It's very odd. Normally moving an email, say from the Inbox to the relevant year's archive, takes "no time at all".

Which is true for all the mailboxes shown on the attached screenshot, EXCEPT for the four at the bottom. Moving even one message from Inbox to Yiddish can take ten seconds or longer (with the dreaded "Not Responding" occasionally). Moving something in the opposite direction is also screwy, only from those four.

I had thought that it was because they're rather large. This first started when there were just Yiddish and MSW, and I split off most of the earlier years into the archives shown. To no avail.

It's only an annoyance, but I'm puzzled about how such a thing could happen.

Also very slow tagging or untagging a message just in those mailboxes.

Moderator Notes:

• need a performance profile https://support.mozilla.org/en-US/kb/profiling-thunderbird-performance

Thunderbird 156 wanted to keep getting a response that my business associate's email account did not exist. I had to have the recipient contact me to get Thunderbird to successfully deliver the email I first sent and responded to. Is this not some Java bug to the domain?

I have no idea what happened to my Thunderbird. I think it might have been an update, because all of my folders are not where they were, everything in the folders are sorted by groups like today, or older. I noticed a bunch of my emails are now in folders marked as a Userfolder#. The emails it contains are those that normally should be in a properly named folder, only those named folders are grayed out. Another issue is that when i try to open an email, it opens it as if I want to reply to it. If I just want to read the email, I have to right click on the email and select open to read it. I have 2 spam folders, no idea why, nothing saves to my draft folder I found out today, I just dont know what happened! I dont think I did anything but I dont know now, as Im beginning to doubt myself. It's been this way for a few days.

I keep getting the following error when trying to download emails from yahoo.mail: Authentication failure while connecting to server pop.mail.yahoo.com Have hundreds of emails sitting in yahoo.mail that I need to load onto my desktop. Any help is appreciated!

I have been unable to send emails for two weeks. I continually get error messages such as "An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: EHLO requires valid address." Another message says to check the SMTP outgoing server settings. I am using Windows 10, which has worked for several years. My email server is mail.twc.com and Spectrum. I can send emails via my iPhone or via the Spectrum webmail, but not through Thunderbird. I have examined my SMTP settings several times and have tried various combinations of settings. None has worked. Spectrum has no help and refers me to you. Can you help? Thank you, Andrew Gurian

How can I change an IMAP server on an existing T-bird account after T-bird deleted the saved password and IMAP server for that account? I tried to change the IMAP server address for an existing T-bird account, but T-bird and/or my ISP deleted the saved password and IMAP server entry for that account, so T-bird cannot get incoming E-mails. I would like to add an/the IMAP server back to the account without deleting the account, adding all of its settings again, and waiting 6 hours for T-bird to re-download all of the most recent 10,000 messages in the Inbox and all of the 15,000 messages in other folders again. The SMTP server and its saved password are still in the Saved Passwords table.

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've been using Thunderbird version 155.0 with only a few issues (reported in other posts).

To investigate one of the issues I've had to create a new profile for testing. I've managed to set everything up except for my default font for outgoing emails. If I send an email with say, four lines of text, I can format each line to be a different font and the received email reflects the different fonts for each line.

But Thunderbird isn't remembering the last selected font. So if I send a second email (without re-selecting any font) the recipient receives it in some naff mono-spaced font. I guess there's somewhere where I can set up the default font for my outgoing emails but I haven't managed to find it yet. Can anyone help?

I am trying to send an S/MIME encrypted email from Thunderbird to:

jobcenter-chemnitz.netzwerkpartner@jobcenter-ge.de

The recipient certificate is provided by the official certificate directory of the German Federal Employment Agency (Bundesagentur für Arbeit).

I downloaded the recipient certificate and successfully imported it into Thunderbird under:

Settings → Privacy & Security → Certificates → Manage Certificates → People

The certificate is displayed correctly there. The email address contained in the certificate is:

jobcenter-chemnitz.netzwerkpartner@jobcenter-ge.de

The certificate is valid from July 29, 2026 to July 29, 2028 and includes E-mail Protection and Key Encipherment.

The required CA certificates are also installed:

BA-Class-1-Root-CA-4:PN BA-VPS-CA-11:PN

However, when I compose an encrypted email to this exact address, Thunderbird reports:

“You have selected to encrypt this message, but the application failed to find an encryption certificate for jobcenter-chemnitz.netzwerkpartner@jobcenter-ge.de.”

Under S/MIME → Recipient Certificates, Thunderbird also shows the certificate as “Not found”.

I have already tried:

deleting and re-importing the recipient certificate completely restarting Thunderbird after importing it manually typing the recipient address in lowercase without using autocomplete checking the complete CA certificate chain temporarily disabling OCSP

None of these changed the result.

My own personal S/MIME certificate works correctly. As a test, I can compose an encrypted email to my own email address without any certificate error. Therefore, the basic S/MIME configuration and my own certificate appear to be working.

When I reproduce the problem with the Thunderbird Error Console open, I get:

NS_ERROR_ILLEGAL_VALUE (0x80070057)

related to:

nsIMsgComposeSecure.beginCryptoEncapsulation

This seems similar to Mozilla Bug 2021265, where a manually imported recipient certificate is visible in Certificate Manager but is not found when composing an encrypted message.

Is this a known issue in Thunderbird 140 ESR, and is there a workaround for using this manually imported recipient certificate?

“My Spectrum email address is [redacted]@charter.net. Spectrum webmail can send and Thunderbird can't receive or send. The outgoing server is mobile.charter.net and the connection times out. I tested the connection from my computer and ports 587 and 465 both respond successfully. Thunderbird is set to No Proxy. when i tried to send today, it gave me this message, "Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) mobile.charter.net timed out. Try again." i contacted spectrum about this and now when i try to send, it says nothing and the message never arrives.