Thunderbird Community Forum

Changed our broadband provider on Friday from PlusNet to EE and, since then, have been unable to reply to emails on my Thunderbird Mozilla account. I am still receiving them but when I attempt to reply I get the message:

"Sending of the message failed.

An error occurred while sending mail. The mail server responded: <pauline@dolhun.co.uk> recipient rejected - relay denied. Please check the message recipient "pauline@dolhun.co.uk" and try again."

Can anyone offer any help please? I am not very computer savvy unfortunately 'Regarding the question below which I have answered 149.0, to be honest I don't know which Thunderbird version I have but I had to fill in something!!

win10/tbird v140.12.1.esr wont d/l from yahoo. logon appears ok but the d/l bar starts & then just times out. This just started 3-4 days ago. gmail & fastmail ok.

I get hundreds of emails a day, so setting an alert for incoming mail is not practical. Is there any way to set an alert for specific senders whose emails need to be res[ponded to promptly? I am not at the computer all the time.

I have been using Thunderbird for many years. I just got a new computer and installed Thunderbird onto it. I have several email accounts for personal, business and clubs so this makes it easy to keep track of. I have some gmail accounts and 3 different yahoo accounts. Now when I get an email to one yahoo account it prorogates to the other two. This never happened on the old computer do you have any idea how this happened, and more importantly, how do I stop it?

I've been using TB for many years, and without warning, when it tries to down load my mail from the Proton mail server, it says it can't find the folder "Inbox". I've tried to "repair" that folder a couple times unsuccessfully. I've restarted the TB program a couple times, but nothing changes. The error shows up on the bottom "instruction line". I've gone through all my settings and find nothing amiss. Not sure where to go from here. -- Just noticed that I had about 80 emails in that Inbox folder that are now missing completely. Normally, I move read emails to there respective folders, and leave important ones in the Inbox for followup. One significant note here, is I'm still using Win 7 premium. So far it hasn't been a problem. Thanks a bunch, Gerald

Edit - continued at https://support.mozilla.org/en-US/questions/1593421

I have an Thunderbird email account both my wife and I use on phones, tablets and PCs. We use imap on phones and tablets, and pop3 on PCs. Occasionally when downloading the email to the PCs the download stops on a specific email and will go no further. All 3 PCs stop at the same email. IMAP can see the email that haven't downloaded, and if I delete with IMAP the email after the successful downloaded email, the pop3 Clients can download the remaining email on the server. This has happened several times and I don't see anything especially weird about the offending email. Usually some small graphics but no large attachment or anything odd? Any ideas as to what is going on?Version 140.12.1esr

I've used TB for many years, and keep it up to date. But it suddenly stopped downloads from my email server. Normally everything comes into my Inbox folder and after reading, they are either put into their respective folders or deleted. I had maybe 60 or 70 retained for later attention. (Like due pymnts)

I've tried everything I know, even the mail server connection, but somewhere in the process, I lost everything that was saved in the "Inbox" folder. I got to looking for the profile file, and only found 1 that was recently dated. Not sure if a rebuild would be advisable. Nearly all my (50+) folders show up as normal. Just can't find why the Inbox isn't recognized.

I tried using TB in both safe mode and troubleshoot mode, to no effect. I DO have win 7 Ultimate and hasn't ever been a problem. The error message I get is: "The mail server for account ***** responded with 'mailbox INBOX does not exist!' The name of the folder is "Inbox" as opposed to the capitalized version, but nothing has changed for years, and never been a problem. Go figure??

After _years_ of use and storage, I'm really hurting without it. Any help or suggestions would sure be appreciated. gshantz

When I send an email, a window pops up that shows the sending progress. Emails appear to send and save to the sent folder just fine, but the window doesn't close and will remain open until I press the cancel button. Is it possible to fix this?

I have been a Thunderbird user for many years, although I stopped updating with 102.15.1 (64 bit) as the new features and benefits did not provide a benefit. In the past few months, emails in my Inbox have disappeared, without being manually deleted. Typically the Inbox will keep emails from today and dated back to about six weeks earlier. Everything else is gone but still on the Rackspace ISP. I have Thunderbird running on two PCs (office and home), one iPad and my iPhone.

My account settings are IMAP, SSL/TTS, and message sync don't delete anything.

I have reviewed suggestions online regarding fixing this; including reindexing, changing settings, etc. but nothing has worked. I know that I can create local folders and save a copy there but I did not have this problem before and it is inconvenient to have to save copies, then remember to look at the saved folder instead of the inbox. According to the tech folks at Rackspace the issue is either within my system setup or some change to the Thunderbird program (although I am still running 102.15.1). My preference is to restore the program to its original functionality instead of creating work arounds. Any advice is much appreciated. Thank you.

On Saturday morning 27 June 2026 I tried to login my Orcon email account via Thunderbird (which I have been using for a long time). But my login didn't work, I got a message saying "login to POP3.orcon.net.nz with username habitation failed." On 30th June 2026 I reported the problem to Orcon.

Orcon gave me the following settings for Thunderbird. I have done that and even made a new account: Incoming Server Type: IMAP Mail Server: imap.orcon.net.nz Port: 143 SSL: Off Authentication: On (username and password required)

Outgoing SMTP Server: Mail Server: smtp.orcon.net.nz Port: 25 SSL: Off Authentication: Off

Since then I have spent many hours and going around in circles with Orcon's Technical Support to resolve this, but no luck. They blame Thunderbird. I used Thunderbird Troubleshoot Mode. The message that comes up reads: login to server mail orcon.net.nz with username habitation failed. Please can you check that your server settings above are correct? And if there is a bug? Irma

Title: POP3 mail delivering into Archives/Inbox instead of real Inbox — folder appears mis-flagged as special Inbox

Thunderbird version: 152.0.1 (Windows 11)

Problem: After migrating my profile to a new computer (copying the profile folder and profiles.ini, both with relative paths), new mail for a POP3 account (server1, account1) is being delivered into a nested folder "Archives/Inbox" instead of the account's real top-level "Inbox".

Evidence gathered so far: - Real Inbox: mailbox://ABC@savba.savba.sk/Inbox — only 1 message, effectively untouched for weeks - Archives/Inbox: mailbox://ABC@savba.savba.sk/Archives/Inbox — 31,186 messages, 10.9 GB, actively receiving new mail (confirmed with a test send) - Both folders display the same "special Inbox" folder icon in the folder pane - Neither folder can be renamed (rename option greyed out on both) — normally only true special folders are rename-locked - Account Settings shows only 3 legitimate accounts (POP3 savba.sk, IMAP Yahoo, Local Folders) — no hidden/orphaned account pointing at Archives - No message filter is causing this (only active filter is an unrelated SpamAssassin rule) - Identity's archive_folder pref is set to .../Archives (not .../Archives/Inbox), so this isn't the manual-archive-target setting either - Checked prefs.js directly: no mail.server.server1.* pref names an explicit "Inbox" folder path, so the special-folder designation doesn't appear to live in prefs.js - Renamed folderCache.json to force a rebuild — did not fix delivery, and also temporarily broke the Send button in compose windows (fixed by restoring the original file) - Ran "Repair Folder" on Archives/Inbox — only rebuilt the message index (.msf); did not change where new mail is delivered

Current hypothesis: The special-folder (Inbox) flag seems to be stored per-folder (likely inside each folder's own .msf index or an internal DB row) rather than in prefs.js or folderCache.json — which would explain why neither cache rebuild nor folder repair touched it. Two folders under the same account appear to carry this flag simultaneously.

Questions: 1. Where exactly is the special-folder (Inbox) designation stored, if not in prefs.js or folderCache.json? 2. Is there a supported way to clear/reassign this flag from a specific folder via the UI or Config Editor? 3. Could deleting just that one folder's .msf file (Thunderbird closed) force it to regenerate without the incorrect flag, without affecting the 31,186 messages in the mbox file itself? Is this safe?

Happy to provide further logs or additional prefs.js excerpts (redacted) if useful.

Thanks in advance.

When I login into Thunderbird, I continue getting the following error message "Login to server imap.comcast.net with username kfn.appraiser@comcast.net failed". I put in correct password and happens again. Mail server is Comcast. Running Windows 11

I am plagued by demands that I allow Thunderbird to "permanently delete all" my email from Gmail. Why would I want to do that????? I'd like for Thunderbird to be able to compose, send, receive, and delete emails in Gmail, but not permanently delete all of my email there. What can I do?

I am using Thunderbird 152 on a Windows 11 desktop computer. I want to be able to include a hyperlink in the text of an email message. Please advise. Thank you.

Martin Belonje

Jul 15, 2026, 13:24 CST

Goodday,

Unfortunately I could not add a screenshot to this message. Under my account [redacted]@zonnet.nl there is a "Postvak IN". This means inbox. In this inbox should new mails appear. Right now there comes nothing in it. However, two lines below there is suddenly another "Postvak IN 22". New emails appear here now. I already tried to drag this inbox into the inbox under [redacted]@zonnet.nl but that doesn't work.

New emails now appear with a yellow bar: The text in the yellow bar at the bottom says: (I translated)

No unique identity was found matching the sender address. The message will be sent using the sender field and the settings of the identity Martin Belonje <[redacted]@zonnet.nl>.

To my opinion this has to do with the fact that the inbox has moved from its original position.

I hope you can help me out.