Thunderbird Community Forum

Greenby Support wants a screenshot of Thunderbird Outgoing Server (SMTP) which I can't find via the App menu or any other means of searching. So I do not know which version we have re your question below and I have chosen one shown at random to allow me to submit my question

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?

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 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!

I have recently closed my yahoo mail account, removed all traces from Thunderbird, but when I start Thunderbird, after a few seconds, I get a Yahoo sign in screen over the top of Thunderbird

In TB prior to v.155, folder message counts were not shown at all if the respective folders were empty. That is, instead of showing "0", TB did not show anything.

Now, after updating to TB v.155.0.1, I see dashes (horizontal lines) in the folder tree to the right of each empty folder.

Is it possible to revert back to the original behaviour and get rid of those unsightly dashes? They only add visual clutter (my opinion, obviously) while not providing any extra information.

Thanks.

Hi, Every time I start Thunderbird from a cold startup, I get the message: Authentication failure while connecting to server outlook.office365.com then.... everything works fine from then on. I can send and receive normally. This can also sometimes happen when I close thunderbird and restart during the day - but not always ! Obviously all the outlook sign-in settings are OK, as it works fine for the rest of the day. Is this known/common/fixable ?

Regards, Paul

Windows 11 (26H2) Thunderbird 156.0 (64-bit)

Anyone know how to use the new setting "mail.addr_book.add_item_default_uri" in 155? The default value is a URI, "jsaddrbook://abook.sqlite", how do I figure out the URI of an alternative? I want to point it to my CardDAV server, do I just set it to the CardDAV URL?

I choose to use POP not IMAP. Yesterday morning, messages downloaded as normal, no problem. Yesterday afternoon, they did not download and I received this message "Unable to write the email to the mailbox. Make sure the file system allows you write privileges, and you have enough disk space to copy the mailbox." I had done nothing at all to my system in the meanwhile, as far as I am aware. I have tried deleting a lot of old emails from my inbox, and emptying the 'Deleted' folder. Any suggestions very welcome.

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?

Hello fellow Thunderbirds,

I have been using Thunderbird for years and had thousands of emails in quite a few folders, with a shit-tonne of filters etc. My emails were running pretty well. I only use two addresses, but the folders help manage everything.

I just got a new computer last week. Prior to switching over to the new computer I read through the 'Export your Thunderbird Profile' help page, and the 'Move Thunderbird data to a new computer' pages. I've tried to follow all the info there (with a glitch, explained below).

I am using a Windows system and have gone from Win10 to Win11.

I have the following data:

• Mozilla Maintenance Service (in Program Files (x86) ).
• Mozilla Thunderbird (in Program Files (x86) )
• Thunderbird (In Users/Username/AppData/Local/Thunderbird) (Contains 'profile' and 'updates'

I tried to swap the above data into the same spots on the new computer, but alas, it's not working. I *may*, however, have fucked it up myself...

So... When I got the new computer, I immediately downloaded Firefox, but, alas, I entered my email's details before closing it down. It did download a few off the server, but only a day's worth (before I realised I screwed up).

As soon as I realised I'd mucked up, I uninstalled Thunderbird and deleted the files on the new computer (you know how when you download it doesn't always remove all the stuff, so I tried to do this).

I reinstalled Thunderbird, but closed it prior to loading the email addresses on (as instructed). I then transferred all the above data into the corresponding file areas on the new computer. However, everytime I try to run the program it just goes to the standard open screen (with the popup that prompts you to enter your email addresses and details into it - see image, below, in case I'm not explaining it right).

Anyway, I'd appreciate any help you might be able to give me as I'm desperate to get my emails running again and have access to all the saved emails which were in my system. Kindly. Larysa.

I'm trying to remove a couple accounts that I no longer use in Thunderbird. A window keeps popping up asking for a password, but the mail service is no longer available. When I click on the red delete button for that account, nothing happens. I've deleted all the mail in one of them which I was able to do as I thought I might need to do that first, but I still can't delete it after that. The other one won't even let me delete the emails. How do I delete these so I stop getting asked to put in a password for accounts that are no longer valid and I don't want anymore?

I have the latest T-bird installed on a latest version linux Mint laptop and occasionally get puzzling errors on Yahoo mail.

Mostly it all works, but Yahoo email errors are often enough to be bothersome and I can't find any information on the rather obsure errors. Been this way through many t-bird and Linux releases.

My other email accounts don't seem to have a problem (gmail, outlook) on any t-bird instances. Just Yahoo mail on Linux Mint t-bird. Here are the errors:

"Please try later" and apparent timeouts on Yahoo mail (on t-bird, of course). This is obvious, but it doesn't happen on my Win 11 and Android T-bird programs.

Operation on yahoo "inbox" did not succeed. Yahoo mail server responded "p." (Yes, just "p.")

Operation on yahoo "inbox" did not succeed. Yahoo mail server responded "UID FETCH completed"

These errors don't seem to happen on Android t-bird or Win 11 t-bird on the same accounts, but I'm not on those for very long.

Any guidance would be appreciated.

Yes, this outlook account was made earlier this year. I've tried all of the "fixes" offered on here and across the internet. I'm changed to to password and got the app password. I've deleted 2FA to see if that would work. I've deleted the Oauth key and it refreshed to a new one. I've done it all and TB-sync is not available to me cus apparently now i'm right outside the app version limit.... how convenient. It's very frustrating as i really like the app and still use it to read my emails but it's very annoying to have to open the outlook app and go through all that just to send an email. I keep getting told it is possible, i've been battling this on and off for months. I cant just get a new email either as i already swapped everything to the outlook one and my work using out look as well. i am able to sync my calendar even but apparently just not my outgoing emails. I would like to transfer my email but the other email i have is a proton email and they are a whole other headache. Please help.

OS: Linux / Android

TB Version: 156.0

Current Outgoing Server Setup:

Server Name: smtp-mail.outlook.com Port: 587 Connection Security: STARTTLS Auth Method: OAuth2 Username: *****@outlook.com

I am trying to migrate from Microsoft Outlook 2021 to Mozilla Thunderbird. I have successfully imported the email from a number of different email accounts. I would now like to import the archived emails held in a number of PST files. The import tool would seem to be what is required, but it does not seem to allow me to select the PST files that I wish to import. I am concerned that it will try to import all email messages from my Outlook 2021. Is there a way of restricting it to just individual PST files?

Mail sent to me as cc: and/or bcc: addressee (but not as a To: addressee) is received at my ISP mail account, but Thunderbird will not retrieve them.

This has been going for a long while it seems, but I don't get much mail addressed as cc: or bcc:, so I only recently became aware of it.

My ISP webmail interface uses Roundcube. Cc: and bcc: messages sent to me show up there. I have Thunderbird 156.0 installed on two macOS 27.0 machines and Thunderbird 24.0b2 installed on Android 17 (includes all updates through Android security update of September 5, 2026). Neither of the three will retrieve the cc: or bcc: messages, but all other e-mail functions work as expected.

My ISP says it's a Thunderbird problem, but I ain't so sure. Any ideas?

This morning, my email Inbox is empty. I use Thunderbird for four email accounts, and three of them are fine, but the fourth one has an empty Inbox this morning. I didn't (intentionally, anyway) move the emails anywhere, and they do appear to be in the All Mail folder, so I didn't lose them entirely. But I keep my emails mostly in my Inbox and they aren't there anymore.

Any ideas what happened to make them disappear and how I can get them back to the Inbox?

Thanks!

“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.