Thunderbird Community Forum

I have been using Thunderbird email for years. Recently, I have gotten this error message: Connection to server mail.5starpros.com:465 failed. I have checked all the settings and they are right for my domain. I called the hosting service to check for email on their end and everything is fine. This message is blocking my domain at 5starpros.com. But, in Outlook on the same computer the same email address is working just fine. Thunderbird has the same settings and is getting my email. Is like my PC is blocking my email address. Can anyone help me with this. It is very distressing.

I keep getting prompt with this message stating the current config is set to block cookies (attached screenshot) and is occurring every interval. I had updated the app yesterday, some how after restarting the computer, it's popping up with the message.

I have been using Thunderbird for years. Suddenly, a couple of days ago, the sent and trash folders no longer show the emails in them. When I use Roundcube online, these files show up there as normal.

I have done considerable research online to solve this problem to no avail. Using AI, they suggest a number of things that I have tried, without solving the problem. Apparently, this is somewhat common. I finally got to deleting the send.msf and trash .msf. This did nothing to solve the problem.

This is very frustrating. What can I try next? I am using Win 11 and Version 152.

Carl

The system was working fine. The next day, when starting Thunderbird (TB, the status line shows logging in to server but loops; no errors or messages, Thunderbird is 'locked out' spinning. I see the normal INBOX page, but logging in never completes. NO CHANGES were made to TB accounts or settings. I have re-installed TB, re-booted, but no change. I cannot check/change any of the accounts or do any further 'debugging' because TB is spinning. The server login is fine because Webmail can be used. Internet connection is fine, because browser works. 1. How can I stop TB from trying to login at start up? 2. What could/would cause this behaviour?

Any suggestions much appreciated.

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

I have no idea why Thunderbird stopped working for me and I can't seem to solve the problem - one day. I got a notification to re set my credentials - nothing since

Hello,

Does anybody knows why or how this happened? Thunderbird has worked just fine since the May 1. My internet connection works well. Has anybody had this problem before?

Thanks

N DC

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

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.

I have email accounts that are with Shaw (shaw.ca) which was bought by Rogers. I've had these accounts for years, and about a week ago the emails were not being downloaded and I could not send emails either. The email server is : Incoming - imap.shaw.ca, security type SSL, port 993

                   Outgoing - mail.shaw.ca, security type STARTTLS, port 587, with domain shaw.ca

I deleted Thunderbird and reinstalled it on my desktop computer that runs Windows 11, and attempted to add my Shaw email accounts using the above email server information, however received an error message that it could not connect to the server. I was however able to set up my Outlook and Hotmail accounts and could receive and send messages.

I also have Thunderbird on my laptop (Windows 11), and the Shaw email accounts were also unable to receive or send, although they were receiving and sending last week.

I contacted Shaw (Rogers) technical support and they said the Shaw webmail was operating because I could send and receive using Webmail, but that it must be an issue with Thunderbird. This did not make sense as I also installed Canary and Mailspring, and was unable to have my Shaw email accounts set up in those email programs with them being unable to connect to the Shaw email server. The tech rep said I would need to contact Thunderbird to have them confirm there was no problem on Thunderbird's side.

I also installed the Outlook email program and tried installing one of my Shaw email accounts using the Shaw server specs, and it installed the account and connected to the Shaw email server. I was able to send and receive emails from it. When I used the same Incoming and Outgoing specs in Thunderbird, Canary, and Mailspring, it would not connect to the Shaw email server.

Any suggestions as to what the problem might be and what might be done to correct it to allow my Shaw email accounts to be set up in Thunderbird would be much appreciated. Thanks.

keep getting connection to sever failed, wont load any emails or send messages, does not show any old emails that were saved, settings are all correct tried all fixes, nothing works ?

After system complete reinstallation Ubuntu 24.04 it is not possible to send mails with SMTP Server. Receiving messages is possible!! Two fault Messages happen, I've two SMTP servers: 1. No connection to SMTP possible 2. Server timeout

And yes, I've checked nearly everything what's to find in the internet, reinstallation, change and check settings and passwords, together with the specialist from my provider. Also my provider is not able to find a mistake. As I've found out in the net, there are sometimes problems to connect to SMTP, but no solution found. Is there some security in the UBUNTU system, which blocks the SMTP connection or is this a bug from Thunderbird? Thanks in advance Andreas

As of this morning I am no longer able to download or send email via my Spectrum email account. A warning message appears next to the account name reading 'The certificate for mobile.charter.net:993 does not come from a trusted source.' The section from the View Certificate page makes it seem like the certificate should be valid:

Issuer Name

Country BE Organization GlobalSign nv-sa Common Name GlobalSign RSA OV SSL CA 2018 Validity Not Before Tue, 19 May 2026 11:45:30 GMT Not After Fri, 04 Dec 2026 11:45:30 GMT . Spectrum of course says it's an issue with my email client. Adding an exception for mobile.charter.net does work, but that doesn't seem like a good long-term solution. When I attemt to get a certificate for the server, I get a 'No Information Available - Unable to obtain identification status for this site'. I am not using a mail scanner and my only anti-virus is Windows 11 built-in Virus & Threat Protection. Any help or suggestions would be appreciated, thanks.

Hi, I use my Thunderbird installation as a feed reader for RSS. Unfortunately, there are two feeds which aren't updated any more. I can't find an error. The feed is OK, I checked the XML file - the new entries are in the feed. The same feed works with a different feed reader. I already deleted the feed and added it again to Thunderbird. That didn't help. I don't know how to find the error. One of the not working RSS feeds is this one: https://mastodon.social/@islieb.rss

When I execute "right click -> Get Messages" on the feed, nothing happens. No error message... What can I do to find the error?

I'm running Fedora Linux 43, Workstation Edition; Thunderbird 140.10.2esr from Flathub. Everything's up to date.

Thanks, Simon

I use Thunderbird when Postbox acquired another. I am using 2 computers - desktop, old (10+ years), still Windows 10, and 2 two emails; new laptop (traveling), Windows 11. I download Thunderbird and set up my accounts - gmail.com and twc.com. Troubles with gmail.com, but finally I set up. However, I can't set up twc.com. I like twc.com-- no reason. (Time Warner Cable (twc) bought Spectrum. ) I can login twc.com webmail. Not Thunderbird. I looked carefully set up, Thunderbird searched, found "Host: mobile.charter.net" (Huh?, , continue, enter my password - "Error: ---". I removed VPN Windows 11, no difference. (Curios, my laptop and Firefox, my bank rejected connection. My desktop and Firefox still connects! I dread the day must update.)

I am look forward yours reply. (Maybe Spectrum is searching to dump twc.com.) Jeremy Fields P.S. I wrote with my desktop - windows 10 -, my new laptop (windows 11) is problems

I have just been updated to a fibre BT account. My Thunderbird e. mail now refuses to let me send out e. mails, though it receives them correctly. It rejects all recipients. I have checked the outgoing server and the settings are correct. This problem is specific to one computer here, others don't have any problems. Despite refusing to send e. mails, my e.mail service provider, Greenby, has received mail from me this morning which is said to be unsent. What is blocking the server?