Please post your Troubleshooting Information. At the top right of the Thunderbird window, click the menu button ≡, then select Help > More Troubleshooting Information. Press the "Copy text to clipboard button" and paste the information into your reply.

Thanks for replying.

I will paste the requested details below.

Firstly, when I try to send a message, I get: "Sending message failed. The message could not be sent because the Outgoing server (SMPT) mail.btinternet.com timed out. Try again."

When I try again, "Sending the message failed. The message could not be sent because connecting to Outgoing server (SMPT) mail.btinternet.com failed. The server may be unavailable or is refusing SMPT connections. Please verify that your Outgoing server settings are correct and try again."

The troubleshooting log was too big to post in full. I've had to remove some. Hope I've not taken out anything that was vital. If I have, let me know and I'll post it separately.

Thanks for helping.

Application Basics

   Name: Thunderbird
   Version: 115.10.1
   Build ID: 20240417192958
   Distribution ID:

   Update Channel: release
   User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:115.0) Gecko/20100101 Thunderbird/115.10.1
   OS: Windows_NT 10.0 19045
   OS Theme:

   Launcher Process: Enabled
   Multiprocess Windows: 0/0
   Fission Windows: 0/0
             Enabled by default
   Remote Processes: 0
   Enterprise Policies: Inactive
   Google Location Service Key: Missing
   Google Safebrowsing Key: Missing
   Mozilla Location Service Key: Missing
   Safe Mode: true
   Memory Size (RAM): 7.8 GB
   Disk Space Available: 779 GB

 Mail and News Accounts
   account2:
     INCOMING: account2, , (none) Local Folders, 0, passwordCleartext

   account5:
     INCOMING: account5, , (pop3) mail.btinternet.com:995, SSL, passwordCleartext
     OUTGOING: , mail.btinternet.com:465, SSL, passwordCleartext, true

 Libraries

     Library
     Status
     Expected minimum version
     Version in use
     Path

     RNP (OpenPGP)

 Calendar Settings

   Home

     Name
     Value

     Name:
     Type: storage
     Disabled: true
     Username:
     URI:
     Refresh Interval:
     Read-only:
     Suppress Alarms:
     Cache Enabled:
     iMIP Identity: id4
     iMIP Disabled:
     iMIP Account:
     Organiser Id:
     Force Email Scheduling:
     Popup Alarms Supported:
     Alarms on Invitation Supported:
     Max Alarms Per Event:
     Attachment Supported:
     Max Categories:
     Privacy State Supported:
     Priority Supported: true
     Event Supported:
     Task Supported:
     Local Time Supported:
     UTC/GMT Supported:
     Auto-Scheduling Supported:

 Crash Reports for the Last 3 Days

 Remote Processes

   Type: Count

 Add-ons

     Name
     Type
     Version
     Enabled
     ID

       Amazon.co.uk
       extension
       1.1
       true
       [email protected]

       Bing
       extension
       1.0
       true
       [email protected]

       Chambers (UK)
       extension
       1.0
       true
       [email protected]

       DuckDuckGo
       extension
       1.0
       true
       [email protected]

       Google
       extension
       1.0
       true
       [email protected]

       Wikipedia (en)
       extension
       1.0
       true
       [email protected]

 Security Software

   Type: Name

     Antivirus: Kaspersky Total Security
     Antispyware:
     Firewall: Kaspersky Total Security

     GPU #1
     Active: Yes
     Description: Intel(R) UHD Graphics 630
     Vendor ID: 0x8086
     Device ID: 0x3e98
     Driver Version: 27.20.100.9664
     Driver Date: 6-1-2021
     Drivers: igdumdim64 igd10iumd64 igd10iumd64 igd12umd64 igdumdim32 igd10iumd32 igd10iumd32 igd12umd32
     Subsys ID: 086b1028
     RAM: 0

     GPU #2
     Active: No
     RAM: 0

     Diagnostics
     AzureCanvasBackend: skia
     AzureContentBackend: skia
     AzureFallbackCanvasBackend: skia
     CMSOutputProfile: 

     Decision Log
     HW_COMPOSITING: available by defaultblocked by runtime: Acceleration blocked by safe-mode
     D3D11_COMPOSITING: unavailable by default: Hardware compositing is disabled
     DIRECT2D: unavailable by default: Direct2D requires Direct3D 11 compositing
     D3D11_HW_ANGLE: unavailable by default: D3D11 compositing is disableddisabled by env: D3D11 compositing is disabled
     GPU_PROCESS: available by defaultblocked by runtime: Safe-mode is enabled
     WEBRENDER: available by defaultunavailable-in-safe-mode by runtime: Safe-mode is enabled
     WEBRENDER_COMPOSITOR: available by defaultunavailable by runtime: No DirectComposition usage
     WEBRENDER_PARTIAL: available by default
     WEBRENDER_SHADER_CACHE: available by defaultunavailable by runtime: WebRender disabled
     WEBRENDER_OPTIMIZED_SHADERS: available by defaultunavailable by runtime: WebRender disabled
     WEBRENDER_ANGLE: available by defaultunavailable-no-angle by runtime: ANGLE is disabled
     WEBRENDER_DCOMP_PRESENT:

Your server settings look good.

Antivirus: Kaspersky Total Security Firewall: Kaspersky Total Security

There may be a problem with your anti-virus/security software. Try to start Windows 10 in safe mode with networking enabled.

Does the problem go away?

Windows safe mode disables anti-virus software. This is a troubleshooting step, not a solution.

Thanks for your reply. I started in Safe Mode but the problem didn't go away.

I'm presently using Microsoft Office Outlook 2007 on an old Windows 8 computer to access BT emails. They come through without a problem. As that computer is probably nearing the end of its life, I wanted a means of keeping my latest emails on my Windows 10 machine which was why I downloaded Thunderbird.

Is there anything else I can try? Do you know if other BT email users have had the same problems with Thunderbird?

Many thanks for your help. I appreciate it greatly.

Try to delete any btinternet passwords Thunderbird may have remembered. At the top right of the Thunderbird window, click the menu button ≡ > Settings > Privacy & Security > Saved Passwords

Thunderbird will then prompt you for the password when it's required.

Thanks for the extra help. I went to the Settings as you suggested. The saved Password for the Outgoing mail wasn't the latest Password. I also deleted the Password for incoming mail.

When I sent a message, I wasn't asked for a BT Password. I immediately got the same message as before: "Sending message failed. The message could not be sent because the Outgoing server (SMPT) mail.btinternet.com timed out. Try again."

I sent a message from another account to my BT email address to check whether messages were coming in okay. Again I wasn't asked for a Password when checking. Nothing came in. The message was listed on BTs webmail but didn't come to Thunderbird.

Sorry for providing such a puzzle! What else can I try, please?

I've also got this showing on the Inbox page. I suspect this could be part of the problem:

Secure Connection Failed

An error occurred during a connection to live.thunderbird.net. PR_CONNECT_RESET_ERROR

Error code: PR_CONNECT_RESET_ERROR

When I click Try Again, the same error message shows.

Just to be sure there are no Anti-Virus issues at play, I have set Thunderbird as a trusted site in the Kaspersky Total Security settings.

The problem will be here!

    Antivirus: Kaspersky Total Security

Have you added the self signed certificate your chosen security software uses to undertake a man-in-the-middle hack of your encrypted communications to undertake it's scanning? https://support.kaspersky.com/common/compatibility/14620

Personally I would like to see a world where security software did not require you to reduce the value of the chain of trust used for encrypted communications, but it is convenient and cheap. That windows makes adding these types of certificates automatically simple via an API to the windows store makes Outlook not have no issues and the user remains blissfully unaware their security in this aspect has been compromised. Thunderbird offers no API to make such modifications, instead requiring a user decision to reduce their security and a manual intervention.

The result is Thunderbird users have issues with this type of supposedly legitimate hacking, but at least they are aware it is an issue that is occurring on their system with the chain of trust. Somehow defender manages without these certificates. See https://www.av-comparatives.org/tests/malware-protection-test-march-2024/ for test results.

Hello Matt,

Thanks for your reply. I've checked out the Kaspersky link you provided. I've attempted to follow their guidance but hit a brick wall when Windows asked me for a file path to export and I couldn't find it. I've been in touch with Kaspersky Chat but their advice didn't help as the person didn't really seem to understand what I was doing. I've raised an email ticket with them.

In Windows, when I get to the Trusted Root Authorities and press Export after clicking Kaspersky in the list, the Windows Certificate Export Wizard asks for the specific name of the file you want to export. I cannot find this file path as it does show up when I hit the Browse files.

There may also be an issue the Kaspersky guidance doesn't cover. The Windows page before the file path questions gives a list of options as to the type of export. The default option is the top one: DER encoded binary X.509 (.cer). I have left this as the checked option but don't know if this is right.

Gosh, this seems much more complicated than I imagined. Thanks for trying to help. I'd be completely snookered without the advice of you guys.

This is what I'd do. Get rid of Kaspersky altogether, and stick with the built-in Windows Defender anti-virus. Defender doesn't attempt to sneak into your secure connection to the server. To avoid problems in the future it's recommended to create an exclusion in Defender for the Thunderbird profile folder. https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data#w_how-to-find-your-profile

I've had Kaspersky on my computers for the last 15 years and never had any virus issues. I'd feel uncomfortable getting rid of them altogether, to be honest. I agree it does seem counter-productive that something that is supposed to be helping makes life more difficult than it should be.

I will see what my email to Kaspersky produces and report back on whether they've been able to help. Does anyone else know how I can trace the file path I referred to in my last post or whether the DER encoded binary choice is the right one?

Many thanks.

I finally dropped paid third party antivirus for the built in Window product when I went to windows 11 a couple of years ago. Up until then I had ESET which covered my windows server as well as the local workstations. I retired and only have a desktop now so could not justify to myself the license cost for something that came with windows and did as good a job on the basics of detecting malware as the expensive products that we have all been using for more than 25years. So far using defender I have had no issues. But then as I linked in my reply, Defender did better in recent testing than Kaspersky and cost a whole lot less.

After contacting Kaspersky about the Thunderbird connection problem when using Kaspersky Total Security, they recommeded that I uninstall it and download their latest software version Kaspersky Plus.

They sent me an activation code for the new product. My original subscription end date remained the same - so no problems there.

After removing Kaspersky from my system completely, Thunderbird worked.

When I installed Kaspersky Plus, Thunderbird still worked. Excellent news!

It appears as though Kaspersky users must have Kaspersky Plus installed in order for Thunderbird to work.

Thanks to you guys on here for helping. I would have probably got stuck without your assistance. Keep up the good work.

I will now spend some time looking at everything Thunderbird has to offer.

Cheers!