Thunderbird Community Forum

Hello, I recently converted a very large OLM (Legacy Outlook on Mac) to Thunderbird on my Macbook. I added an Office365 (work) Account to Thunderbird, and the Outlook Addon App for Thunderbird. I can receive emails to the Office365 account no problem, but cannot Send emails from the Thunderbird (Host) Office365 email, unless I select the Default Outgoing Server which is a different email. I have reset Passwords, related Server settings, and Account Config settings numerous times.

The only other option is to send from the Outlook Addon App ,,, this works fine, But I cannot access the Thunderbird Local Folders from the Outlook Addon.

Any assistance with this issue is truly appreciated. TD

Not sure where/how to post this, so starting here (and happy to move/amend this posting as appropriate.) 15-Oct-2026

Background: I've got a yahoo ("free") email account for many years, and wish to move the current contents of my Inbox to a folder (on imap, not local). Recently yahoo appears to have moved to "cloud" arrangement internally (not sure, but it appears to be the case.) The problem I'm experiencing (below) I believe may be yahoo's back-end cloud processes getting out of sync with Thunderbird's view of the same activity. Therefore, I'm seeking help on how to accomplish this (=I don't think there is a bug in Thunderbird, rather this is a plea for how to manage yahoo's email service for my account.)

Symptom: Moving large number of emails between folders both hosted on yahoo, peers to my inbox on yahoo, using imap - the "export" imap service). Thunderbird says it completes the task, but many (not all) of the moved emails re-appear in yahoo's inbox after a short time, so this makes moving a large (more than a few hundred) emails a *very* laborious process.

What I'm trying to do: I wish to move my current inbox (has about 7.5K messages) to an IMAP-hosted folder (same account, etc.,yahoo email would see this folder as a peer to inbox). When I select all of the messages on inbox and tell Thunderbird to move these to the local folder, thunderbird appears to indicate the task was completed. If I move a very small number of emails at a time, that does complete successfully (=thunderbird says task completed, and the moved emails do not re-appear in yahoo inbox.)

Thanks for looking at this (long) posting and (particular to moderators) if I've posted this incorrectly or in wrong place, please assist!

Dave

As of Oct 12 2026 I also have this issue. About a week before the 12th I was getting messages that I needed to sign into my RCN account which I would do and it just kept asking me. A few times each night to start then right before it shut me out I had over 50 of these messages just flooding my screen. I never did get a screen shot of that message, but did for the 2 error messages I got later once it shut me out. I shut down my computer the night of the 11th then when I signed back in on the 12th I could not send or recieve any emails. SOmething similar had happened before, but when I shut down again it went away. This time it did not. I then tried to access my emails thru the webmail I can access, but that also had shut me out. I also tried my tablet, a borrowed smart phone, but I could not access anything for my emails. I troubleshooted with my email company and my internet company, but they found nothing. Then I shut off the wi-fi on the smart phone and bin go I could access the webmail. But I still cannot find anything on what to do to fix this. I use RCN for my email, Spectrum for my internet. It is a POP3. Running Thunderbird version 153.5 Oesr (32 bit) Meadow, which says it is up to date. I have norton 360 anti virus & do not use VPN. I disabled my Auto-protect and firewall on the Norton and that did not change anything. I have sent the error messages to RCN and also troubleshot with Microsoft and had some hints, but nothing has come of that yet. Here are the screen shots of the only 2 things I ould capture. The error message was when I was trying to access my email thru Thunderbird. And it came up every time I tried to send messages, not that does not show up anymore and nothing happens when I try and send anything. The second one was when I was trying to access the RCN webmail and it would not let me in on anything I used. Until I shout off the WI-Fi. Then the smart phone could access my webmail account.

I use Thunderbird with a info@... account hosted by TransIP.

When I send an email, especially when I reply to a previous email and even more when this was my own email, the sent email is not always saved in the Sent folder: neither in the webmail of TransIP nor in Thunderbird. It seems random when emails are and are not saved in the Sent folder.

The replies are sent through; the recipient receives them.

What can I do?

Despite my attempts to find an error in my outbound mail settings, I keep getting the message below.

The test of the connection to the server passes everytime, but the mail form will not allow mail to be sent.

It's the ESR version. It all started when I added a vcard to my outbound mail.

"Sending of the message failed. An error occurred while sending mail. The mail server responded: Sender refused. Please verify that your email address is correct in your account settings and try again."

I have 5 Gmail accounts they're all configured the same I automatically let thunderbird install two but none of the other three will connect i have tried everything i can think of but can't get thunderbird to connect to my gmail account . the gmail accounts are all configured the same and i'm using the same thunderbird configuation

For some strange reason, I have one message in my inbox that does not display in the window below it (just a blank window) and the message subject line can not be deleted at all. Message title has been there for a week now, shows up every time I start Thunderbird but it can not be displayed or deleted. I have received, read and deleted dozens of message since, it just remains as if haunting the app in defiance of any common sense at all. How do I delete it?

The image shows the message selected and the blank window below, once I select another message and then go back to this rouge message, the previous messages window remains, the blank window does not come back up, Indicated to me that there is nothing in this rouge window to be displayed, hence it is blank if the first message selected.

Hi I have four IMAP email accounts configured in Thunderbird. Three get email from my servers the fourth from Google mail.

I am finding that one of the accounts emails are also ending up in Google mail, the other two are functioning normally.

I have checked for email forwarding etc and cannot find anything.

I removed the account, leaving the Gmail account alone, from my mobile and the phenomenon stops till I fire up the PC.

Anyone got any ideas?

Jules

Hi, my mozilla has just stopped dowloading messages to my laptop. Oddly, any messages sent seem to be received, and a test to my phone to myself verifies. Any suggestions please I would be most grateful for!

I have 5 Gmail accounts they r all configured the same I automatically let thunderbird install two but none of the other three will not connect i have tried everything i can think of but to no avail

При отправке сообщений перестала работать функция сохранения копий в папку ;Отправленные", в уведомлениях появляется сообщение: Предупреждение от учётной записи «ur@aliotplyus.ru»: append Failed to store message. Please, try again later. sc=iXL0I30LkCg0_2026-10-13-05-35_

I haven't had my new email downloaded from my Yahoo mail accounts since 10/8/26. Occasionally, a few emails appear, but they are duplicates from earlier dates, as far back as about 9/27 or 9/28. I have emails from a gmail account that I appear to be getting in T-bird normally. Email seems to be getting through ok on webmail (Firefox, Windows 11). I'm also getting mail on Android (Galaxy S23, Yahoo mail app) and on iPad (also on Yahoo mail app.)

For a few weeks now we have been unable to send emails through tbaytel server via Thunderbird. We get SMTP error. This happened after recent upgrades to Mozilla. Any idea when a fix will be out?

Kan ikke modtage og sende mails. Får følgende besked - Kunne ikke skrive mailen i mailmappen. Sørg for at du har skriverettigheder til filsystemet, og at du har nok diskplads til at kopiere mailmappen.

I get "connection to server pop.mail.yahoo.com timed out" every few minutes. mail is not usually delivered, and some mail that's delivered is from two-three weeks ago that I've already gotten. It seems that I've stopped receiving mail for account "redacted@frontier.com" after 10/8/26. Mail that's sent to other accounts seem to be delivered OK, but mail that's sent to this account doesn't show up. I've received at least some mail for account "redacted@frontier.com" for 10/9 and 10/10. Not sure if I'm getting everything. Mail seems to be received at the yahoo.com website for both email addresses [redacted@frontier.com and redacted@frontier.com]. At least I hope it is! Mail also seems to be received using the yahoo app for Android [phone] and yahoo app for iPad.

My @googlemail.com account has been working in Thunderbird for years. Two days ago it stopped. No incoming e-mails and attempts to send e-mails from Thunderbird result in the outgoing server timing out. I can access direct at gmail.

Please note that my previous e-mail: alan.rhodes@talktalk.net is no longer available The replacement: alan-rhodes@outlook.com has been blocked by MS-AI (It didn't like a circulation e-mail to 60 members of my local history group) The only working e-mail I have is the current problem one: rhodes.alan1@googlemail.com