Forum zgromaźeństwa Thunderbird

Thunderbird says "certificate for mail.capsense.com is not valid for that server..." and hangs. Then awakes in 10 minutes.

I've been getting this message for months without problems.

My Gandi accounts will not connect. I know they are correct; I know my passwords are correct. They are my main emails; if I cannot use them, I cannot use Thunderbird?

I'm confident that this is not a Spectrum/Charter issue as I can log into their webmail client and send mail. I can also use the Mail app on my iPhone and send mail from my user@san.rr.com account. My settings are below and have not changed in many months (when SMTP was still working). I've also checked "Saved Logins" and verified that there are entries for IMAP and SMTP and that the password for both is the same and is correct.

Description: IMAP Mail Server Server Name: mail.twc.com Port: 993 User Name: user@san.rr.com Authentication method: Normal password Connection Security: SSL/TLS

Description: TWC SMTP Server Name: mail.twc.com Port: 587 User Name: user@san.rr.com Authentication method: Normal password Connection Security: STARTTLS

This issue started last week on my Windows 11 PC (which has had updates paused since last month). I was previously using TB 128 and have subsequently updated to 140 and repaired my inbox trying to find this issue. When I attempt to send a message, I see "Status" Sending Message..." and a blue progress bar that never changes (TB_sending.png). The dialog box remains frozen for multiple minutes. I had seen a connection error message to SMTP in the past, but it usually disappeared the same day (see other screenshots). It feels like TB is not making a good STARTTLS handshake with mail.twc.com. I've tried switching to SSL/TLS port 465 and that has the same issues.

Hi:

I'm fairly new to Thunderbird-I've only been using it for a few months. For the first while, everything was working fine. Now, almost all links in emails don't even open a browser window. Those rare ones that do open a browser window never seem to resolve or draw a page.

I don't remember changing any security settings from the defaults. What should I check to prevent this? I'm savvy enough to know what to click on, and what not to.

Thanks in advance

Thunderbird not connecting to server. It says timds out and an error occurred connecting to mobile.charter.net. I can neither send or receive emails. This started 8/20/2026

I've had AOL for an Email provider for several years now. I rarely went to the website to check my Email cause Thunderbird was linked to it. But today, AOL seems to be turning off my Thunderbird (I can't send or receive Email at the moment). It's like malware with the continuous popups making me log in to AOL to use Thunderbird but then ending up on some Yahoo Oops screen. I've been using Thunderbird since before I transitioned to AOL after moving.

It's been working fine up until today. When I do anything on Thunderbird, the annoying popup screens appear wanting me to log in. Any ideas? Have I been hacked?

Здравствуйте, уважаемые. Много дней пытаюсь начать работу в Тандерберд. Делаю всё по инструкции, всё идет хорошо. Создал у оператора почты специальный пароль для Тандерберд. На последнем этапе, после ввода этого пароля появляется ошибка (см. вложение). Никак не могу это побороть. Помогите, пожалуйста!

I downloaded the version on the site but I can't get it to accept my password all I get each time is this at the top of the box

Component returned failure code: 0x804b000a (NS_ERROR_MALFORMED_URI) [nsIIOService.newURI]

Just how am I supposed to understand what that means. I would be grateful for any help you can give I've been using Thunderbird for over 25 years without any problems, I had to reinstall Windows and now I've got this problem.

Recently I posted about this problem here: https://support.mozilla.org/en-US/questions/1580858 In sum, I was having problems both in downloading messages from the Spectrum server and also with sending messages. I've attached screenshots of the error messages.

Matt and David kindly posted some helpful responses. The problem then seemed to spontaneously solve itself and I breathed a sigh of relief. Then a few days later it re-appeared.

This time it's not quite as bad in that I'll get the error messages but then usually a few minutes later I can download the messages or send an email. But it's still a real problem.

I called Spectrum again and this time the rep was adamant that if I can still use the Spectrum webmail feature (and I can), then it's not a Spectrum issue.

Last time Matt asked about my antivirus. I use Windows Defender (and occasionally do a manual scan with Malwarebytes free version), so if I understood him right, I should be OK as far as antivirus interference.

Matt also suggested I set TB so that I download messages at startup and every 15 minutes. I was set to every 10 minutes so I changed it to 15.

Matt said for me to check the Activity Manager. I've attached a screenshot of what that showed a few minutes ago. But I should note that this was after an error message displayed but my email downloaded anyway.

Finally, Matt said I should check the Error Console (Control + Shift +J). I've attached a screenshot of that. He also said I should use the trash can to clear it, so I did. He then said to press Shift + F5 to attempt to get my messages. But on my laptop, F5 just dims the display so no dice on that. But I have a second laptop and F5 is "neutral" on that one so I tried it there. I didn't get any new error message.

However, one of the screwy things is that sometimes I get all my messages as normal, but only after the "Can't connect to the server" message displays. And that's what happened with my second laptop above.

I hope I've provided better info. this time. And I hope you gents can help me with this mess.

Thanks,

Andrew

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

Hi All,

I am on the latest release 156.0 on Windows 10. I have 3 email accounts, 2 gmail and 1 yahoo. The Yahoo account has been giving me problems since the last 2 weeks. Mind that yesterday I have a completely new Windows 10 installation so also TB installation is new.

I have renewed the Oath login, all messages were downloaded without a problem, but once in a while I get different notifications about server errors such as the ones below. There's also a third type of message error but haven't been able to get a screenshot of it.

Could someone please help me to solve this issue? I really don't understand why the problem is intermittent. Thanks in advance!

How do I access the notification messages so I can post them here? Because there is like 12 or more a day on each machine from multiple accounts.

I got one that mentions restricting the number of concurrent threads using the IMAP interface but no clue as to how to restrict TB from making multiple requests from multiple accounts to the same server at the same time.

i have an account that runs through gmail. survey@cornerstonels.net I switched to my sons laptop because for some reason AMD Ryzen chips seem to run my drafting/engineering software better. I was always able to make thunderbird work and it worked great. since this new version with the "account hub" I can't get it to connect to gmail. i have tried at least 10 different times with the correct settings a couple of times and different settings the others. I donate because thunderbird works so well. Please help. I wish i could just download an older version of thunderbird without the account hub. I get the error "component returned failure code:0x804b000a" (NS_ERROR_MALFORMED_URI) [nsllOService.newURI}

I receive this reply when launching email: "Looks like there’s a problem with this site https://outlook.office.com/owa/ sent back an error. Error code: 401 Unauthorized Check to make sure you’ve typed the website address correctly."

Thunderbird suddenly stopped working properly today, 15 September 2026. Webmail for the same email account is working normally: I can both send and receive messages. However, Thunderbird is having problems with both incoming and outgoing mail. • Thunderbird connects to the IMAP server, sometimes very slowly, but then does not retrieve new messages. • Sending a message from Thunderbird fails because it cannot connect to the outgoing SMTP server. • Thunderbird's own update also fails. This has never happened to me before. • I have restarted Thunderbird and also restarted the Mac, but the problem remains. • I have not changed any Thunderbird account settings. The fact that webmail is working normally makes me wonder whether this is a Thunderbird problem rather than a problem with the email service. Has there been a known Thunderbird problem affecting connections to mail servers or the Thunderbird updater, and could these problems be related

Hi, Every time I start Thunderbird from a cold startup, I get the message: Authentication failure while connecting to server outlook.office365.com then.... everything works fine from then on. I can send and receive normally. This can also sometimes happen when I close thunderbird and restart during the day - but not always ! Obviously all the outlook sign-in settings are OK, as it works fine for the rest of the day. Is this known/common/fixable ?

Regards, Paul

Windows 11 (26H2) Thunderbird 156.0 (64-bit)