Thunderbird Community Forum

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?

I have been having troubles logging in with my Microsoft email account on Thunderbird (hotmail). When I fill in the name and email address, a pop-up appears with the OAuth2 authentication but the only thing that ever appears in this pop is the message "Unable to connect" with some additional possible explanations.

I have looked online a lot for solution but nothing seems to work. I have cleared the cache, removed all mentions of the email account (it was working before until I added a passkey to the account).

Other reasons I have seen is that the request might be intercepted by certain problems like Apache or Nginx etc. I am running an instance of Nginx on my home server, which is a different device. But I have temporarily turned it completely off but it did not change the situation. The same story with and instance of PiHole, it turns on my homeserver which is a different device and also had to turned off.

The machine I am running Thunderbird on is a Windows machine. I have also tried booting into safe mode with networking but also that did not do anything.

I have tried copying the url on the top of the pop-up window and pasted into several web-browsers. There is does load and I can select the correct passkey to login. But the data that comes back from it is not being given to Thunderbird of course so it does nothing. But the fact that it is able to load outside of Thunderbird makes me think it is a problem on the side of Thunderbird.

Could you perhaps help me set up my email on Thunderbird?

I have had Mozilla Thunderbird and VPN for some years and no problem but now Thunderbird will not receive or send email if VPN is on. Also there are now a number of sites that will not work whilst VPN is on. I have this on a Windows 11 desktop.

I use thunderbird for a long time. all of a sudden, I can see the addresses of the mails that have arrived, but I cannot open them - I get the message "orange (imap.orange.fr) is unable to connect to thunderbird". I cannot send anything - message "close the program or wait for the program to respond" - I wait for a long time, a little circle keeps turning - that's all. the mail-orange functions without problems, but I prefer thunderbird. what can I do to re-establish the connection orange-thunderbird? thanks - sigrid

I'm using thunderbird 149.0.1. I'm trying to add a microsoft exchange account (@outlook.com). Using the account hub, after I entered the full name and email address and did the two-factor authorization, I'm stuck on the second screen (see attached). According to the instruction , I should not enter my account password in the first dialog box. However this is not possible since the password field is required. If I enter my account password in the password field, and leave the "Your login" part blank (or fill it with my email address), the window would complain "Exchange auth error" after I clicked continue. If I put a random string in the "Your login" field, clicking continue would lead me to a microsoft signin dialog, and if I sign in with my credential and password, the same "Exchange auth error" would still appear after I finished all the steps in the microsoft popup.

Couple months back had to restore computer. Wouldn't let me add my POP gmail account, said had to use IMAP. POP was no longer accepted or something to that effect. So I got IMAP set up. (Of course, I did save my old POP folder with some messages in it.) Ever since setting up the IMAP folder I only get maybe 30 messages each morning. Never more. Which is no way right. I've googled and tweeked the synchronization/storage settings and the server settings. Nothing works. I'll spend hours googling suggestions and trying them, then get frustrated and move on. Then a week or so later I go thru it all again. Nothing changes!! Still only get the very few emails each morning. About 30 or so minutes after the initial download of messages, I'll get a pop up saying imap connection lost. This is SO frustrating. I have no idea what to try next. I never had this kind of issue with any of my POP accounts. Any suggestions? I've probably already tried them but will certainly give it another try. Thanks! Lynn

I have an account with a Spectrum tx.rr.com address. I use Thunderbird to view and send. The email account is set up as POP3 in Thunderbird. It has worked well until the last couple weeks when I started getting sporadic errors from Thunderbird saying "could not connect to server mail.twc.com; the connection was refused." then a few minutes later it works. Sometimes this happens on the Send and sometimes on the Receive.. I believe the account is set up correctly and I never have an issue through webmail. This can happen 5-10 times/day. It is annoying. Any suggestions on how to fix?

Retrieval using the IMAP4 protocol failed for the following message: 18241 comes up every time I use Hotmail. works OK on my G-Mail account. Started after I was forced to delete and reload the programme.

As of a few days ago, I have the latest thunderbird installed and can't say when this began happening, but despite it working for years with two gmail accounts, neither gmail account will now sync / connect and it has authorization issues.

I've then tried running thunderbird in a sandbox / uninstalling / reinstalling / deleting the user profile / registry entries, you name it...when setting up a gmail account in thunderbird, an error of "Authentication error. Unable to log in at server. Probably wrong configuration, username or password." come up, despite the password being verified as correct.

If I manually setup gmail using the gmail settings, of imap.gmail.com / port 993 and SSL / TLS and Oauth2, and do a test, I'm met with "Connection to server.imap.gmail.com:993 failed"

Nothing has changed on my computer in the time leading up to this not working. No windows updates performed...no changes to the firewall etc. You name it. I've checked it all.

Strange! Any ideas? Thanks!

I have been using Outlook Lite to keep my work inbox separate from my personal, I was going to switch over to Thunderbird however I need authorisation from my IT Dept to allow access. What do I need to detail in the request to them in order to quickly / easily get them to process this?