Thunderbird Community Forum

My Thunderbird version is 153.2. My email provider is Yahoo.. I use the POP protocol and have set it up so that messages are left on the server for this particular email address because I want to hang on to several important emails. I am not sure if I should be checking "Until I delete them" but it is checked right now. Leave messages on server for X number of days is unchecked. I also have a few other Yahoo mail addresses on Thunderbird also set up using POP but the messages are set up to be deleted on the server so they seem ok so far.

Basically when I delete messages in Thunderbird, it also deletes my messages in my Yahoo webmail inbox and it goes to the trash. When I delete messages directly in my Yahoo webmail, nothing happens. So I then transfer the emails that ended up in trash of my Yahoo webmail to my inbox and they are of course downloaded again to Thunderbird. When I delete these emails in Thunderbird thinking that nothing will happen in my webmail since it is set up to POP and messages left on the server, the messages get deleted again, causing an endless cycle of transferring emails to inbox, downloading them on Thunderbird, deleting the unwanted emails on TB, then seeing all my other emails disappear on my Yahoo webmail inbox.

It started a few days ago. There was a random glitch (not sure if it was on Yahoo's end) that led to the OAuth dialog window popping up every time TB downloads mail from Yahoo. Initially I didn't handle this properly and it led my inbox emails going into my other Yahoo mail accounts. I have finally fixed that glitch and emails appear to be downloading properly to their respective inboxes. But I cannot seem to figure out what is causing my emails to be deleted from the POP server. Should I be unchecking "Until I delete them"?

I have been trying to set up Thunderbird Mobile on my Android phone. I scanned the QR code to export my settings. However, when I open the app on my phone, the only options I have are "Add an email account", or "Sign in with Thundermail". The instructions state that clicking on "Get Started" should bring up the option to "Import Settings" but it does not.

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

I receive this reply when launching email: "Looks like there’s a problem with this site https://outlook.office.com/owa/ sent back an error. Error code: 401 Unauthorized Check to make sure you’ve typed the website address correctly."

Since yesterday (15 September 2026), my Microsoft Account has not been working properly. I managed to get round the problem by deleting my cookies. Then the update to version 156 was released, and after that Eule became incompatible. When can we expect an update to make it work again? Thanks.

I have been using Thunderbird for a while.. I could always filter messages easily to help with mailbox cleanup, now it seems to have stopped working or a setting has automatically changed.. When activating Quick Filter, I could type in the 'Filter Messages' box and it would start listing the mails in that inbox as I typed, now it doesn't happen anymore..

I can not create a new email account for the email : info@ecomtehpro.ro. I have already an email account: office@ecomtehpro.ro. Please give me a solution to create the new email account. Thank you.

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!

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)

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 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

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!