Thunderbird Community Forum

Hello, from time to time my Thunderbird on my desktop PC running windows 10 doesn't receive emails, while they arrived on my I Phone 8. Checked my Telstra web mail, all emails are there so what is stopping getting to my desktop PC? I thought the Thunderbird receives emails than synchronize with my I Phone? As you can see from my 2 images the Telstra is up to today as is my I phone But Thunderbird is 3 days beyond. Tomorrow it may back to normal or the next day? I am returning to this message the next day 16/06/2026 1 more message on my I Phone, still nothing on my Thunderbird.

An other problem I get with Thunderbird is that a message appears on the right bottom of my screen: "Mozilla Thunderbird Connection to server mail.bigpond.com timed out" and/or "failed to connect to mail server imap.telstra.com" If I try to send an email after the above notifications, I get the "Connection Refused". I know than to just walk away. I am using Starlink as Telstra here doesn't work as I am on the fringes of Melbourne in a BLACK HOLE. Any help will be gratefully received. Thank you for reading this. Regards Ilio Pieroni

It was working fine on the new computer until yesterday. Now I get a pop-up box that says: ' Unable to connect The connection was refused when attempting to contact localhost.

The site could be temporarily unavailable or too busy. Try again in a few moments.

If you are unable to load any pages, check your computer's network connection. If your computer or network is protected by a firewall or proxy, make sure Thunderbird is permitted to access the web.

I have four different email accounts. A week ago, all incoming and outgoing traffic suddenly stopped . Webmail works normally. I have no viruses, trojans, etc. I deleted one of the accounts and tried reinstalling it. I can't do it anymore. The system keeps responding: "Unable to authenticate to the server. Username or password configuration may be incorrect." But they are all abolutely correct. I don't know what else to do. Any clue? Thanks

My name is Barrie Johnson. I have been a Mozilla Thunderbird user for my e-mail services for many years. In the past couple of days I have been getting messages from Google telling me that my e-mail provider - i.e. Mozilla Thunderbird - will not allow Google to access it, with the result that I cannot get to a current version of my Inbox and there is no trace of my calendar details. Can you please help me?

The issue has been "An error occurred connecting to mail.mediacombb.net:993." on the server page, where you can "test connection to server" in Account > Server Settings > Security Settings. I get the same error message for each four different accounts. I have no problems with the other two different accounts not associated with Mediacom (MC). I contacted MC and they said my settings were correct and to contact TB. I have read several posts with no real solutions except that was resolved through an update. I plan to switch to a different Linux distro later. I am currently using Big Linux Manjaro with the latest update. Note that I had no problems with TB until last month. I do not do the uninstall/reinstall apps unless it will resolve my issues as a last resort. Second, sometimes I receive MC e-mails and did not run the "test connection to server," then until today while troubleshooting for several hours. I was trying to send out an e-mail, which I had no problems last week. I already went to Account > Server Settings > Advanced and changed the "Maximum number of server connections to cache" from 5 down to 1 with no luck.

  The e-mail server settings are:

imap.mediacombb.net 993 SSL/TLS Normal Password and smtp.mediacombb.net 587 STARTTLS Normal Password They have not been changed since I switched from windows 10 to Zorin 18 to currently Big Linux Manjaro. I attempted to locate a method to check if the server settings were correct via Terminal. M$ Outlook has a test page that you can send to yourself or another e-mail account. Last, MC tech informed me that M$ Outlook is more friendly than TB. I know that I have used M$ Outlook for years and rarely had any connection issues unlike TB. Unlike Evolution, which was my first after M$ Outlook, TB is much better and easier than Evolution. Thank you in advance for your time and advice.

All was well until about six months ago. When I try to connect to my provider TB won't connect. BUT. At other times it will connect then every few minutes will try to connect again - then again .... I get this message "Connection to the server mail.comcast.net timed out". Then I get this message each time it fails "Login to server mail.comcast.net with username 170834000 failed". It keeps asking me to input my password even though everything is working appropriately. Then at other times it says it doesn't connect but it has connected and it still continues to ask me for a password.

I have uninstalled TB and reinstalled it thinking that would fix it - it didn't. I have changed my password - again to no avail. I let TB choose where to put things and configure each item appropriately. I don't try to get in the way of what works.

Comcast is apparently getting out of the email business and asking everyone to move over to their chosen substitute (Yahoo.mail) and I have not chosen to migrate at this point. Maybe that's the problem. This is the message I get each time I log into Comcast.net:

"A better email experience is now available for you

You're invited to upgrade your email account to Yahoo Mail, so you can enjoy a more user-friendly experience. Your email address, messages, folders, and contacts will not change.

With Yahoo Mail, you'll enjoy enhanced security, a built-in calendar that's easy to use, AI-powered inbox organization, and a top-rated mobile app for easy access on the go."

I am not aware of any changes in the settings from before when it was working well and now when it seems to be erratic.

I am not terribly computer savvy, but I'm usually able to trouble shoot and fix the issues that confront me. This time I'm out of my league! I need help.

Thank you for helping me.

Sometime ago, Thunderbird stopped being able to connect with my GMail and Hotmail email accounts. I guess this had something to do with the change to OAuth authentication. I then switched over to Yahoo accounts which worked perfectly until last night when I installed the latest update, i.e. 153.0.1esr (Meadow). Now, I cannot connect with ANY account whatsoever. Thunderbird just stopped working in my two Windows 10 laptops and it does not seem to work on the Windows 11, either, although I have only tried Gmail accounts on that one (without the update), as I cannot possibly be left without an email handler.

If I try to download my emails, I get a screen that tells me that I should “Turn-off ad blockers“ and “Enable JavaScript“ in my browser, but I have tried several (4) browsers as default with the same result. I don’t have either ad blockers or cookie restrictions in any one of them and JavaScript is enabled in all (it is now by default).

I have downloaded and installed “eM Client” and it works *perfectly*. However, I would loathe to have to abandon Thunderbird and get used to an entirely new program, but which is what I will have to do if this thing is not resolved ASAP.

As mentioned, I think there has to do with the OAuth authentication system.

I have even tried ChatGPT, without success!

And there is no way to revert to the previous version !!!!!

Please do something NOW, or it is, regrettably, goodbye Thunderbird!

When I compose an email, often a pop-up interrupts me to say "Your draft message was not copied to your drafts folder (Drafts) due to network or file access errors. You can retry or save the draft locally to Local Folders/Drafts-[my email address]."

It then gives an option to retry (which always fails), save or don't save. It's annoying because it pops up repeatedly when I am writing, and concerning if my messages are not being automatically saved.

Does anyone know why this is happening or what I can do about it? Thank you!

Only a recent problem. I can receive emails just fine; only the sending of emails is affected. On the same computer, I open the Gmail website in my browser, and I am able to send emails just fine.

I checked my security program, Bitdefender, and there are no notifications relating to this issue.

Any help on what to check next?

Why am I getting this message when I try and send an email from my Mozilla email client: Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.gmail.com timed out. Try again.

I've successfully connected to a hosted Exchange server through EWS and NTLM authentication (kudos BTW). But there is a problem - often during operations against EWS I'm presented with "Login to account XXX failed" "Login to server YYY with account XXX failed". I can ignore it (cancel) and it will work for seconds or minutes but eventually reappear. Sometimes it's very frequent, sometimes is here and there. TL;DR; connection works, I can read directories and e-mails.

From looking at development tools I see these scenarios: 1. POST requests return 200 always (no messsage of course) 2. Eventually a POST would return 401. Then Thunderbird issues a GET, it returns 401 as well but response includes header WWW-Authenticate: NTLM XXXXXX. Then another GET is issued containing header "Authorization" with the value from previous response. This time it gets 200 and continues without POST requests without a dialog. 3. Sometimes there are more POST requests with 401 (I assume in parallel) before a GET is issued and then I see a dialog. Sometimes it recovers (regardless of whether I cancel or retry), sometimes gets stuck with 401 with dialog reappearing each time it tries something. This case it's similar in sense that thunderbird issues GET with 401 and WWW-Authenticate header, issues another GET with Authenticate header but still gets 401.

If I had to guess I'd say the problem happens when POST requests are issued in parallel, not sequentially. OTOH it might be a problem at the server, but it isn't very likely.

Been struggling to get any of the 4 different accounts from PennTeleData at my body shop to connect to thunderbird. They were working yesterday and all of a sudden no good this AM. I can access my PTD email through their web browser and they don't have any support for a 3rd party program. Sure wish there was someone to call at mozilla. I have exhausted soooo many different options all to no avail. Any advice or questions for me to better let you know what my issue is?

I cannot set up my yahoo mail account in thunderbird. first, yahoo does not let me log in using firefox (all extensions off). I set chrome to my default browser. chrome at least allows me to log into my yahoo account directly. First part of set up is okay: server setings, imap etc. then thunderbird wants to connect to yahoo.com. Using chrome I can log in. It then tries to open some file and returns an error message, "no app found." I attach some screen shots.

I am using Ubuntu 24.04LTS with all current updates. xdg-com is installed. the version is 1.1.3. Thunderbird version is current: 153.0 (64-bit).

What is the problem?

I am using the Thunderbird software (140.7.1esr 64-bit) for mail merge purposes on a Windows 11 operating system. However, when I start the mail merge process, it begins initially but then automatically disconnects before completing the task.

Due to this issue, I am unable to complete the mail merge properly. Kindly look into this problem and provide a solution as soon as possible.

Thank you.

Trying to send 3 different emails. Hit send and get: 1) Your message was sent but a copy was not placed in your sent folder (Sent) due to network or file access errors. 2) Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.gmail.com timed out. 3) Your draft message was not copied to your drafts folder (Drafts) due to network or file access errors. How can I get these problems fixed?

Whenever I start Thunderbird, I get multiple (2 or 3) connection reset errors for random CalDAV calendars. When I sync the calendars, there are no errors reported and the exclamation mark on the effected calendars goes away and 153 and they are refreshed.

How can I solve this?

I am getting the error "connection timed out to connect to SMTP server". I am running on Linux Mint. The same setting do work on MacOS so there is no wrong config or broken SMTP server. It was working well since a couple of years. I also tried troubleshooting mode but still the same.

Cheers, Thomas