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I've purposefully used the environment variable to disable the security sandbox.

How can I acknowledge and hide the persistent warning? Is there any about:config value for it?

Thank you!

I have had Thunderbird on my HP laptop for several years. Everything has worked perfectly. BUT, I cannot receive Email, starting yesterday. When I click the Get Email icon, nothing happens. My Email server on Comcast is getting Email which I can see and read, but Thunderbird is not getting the Email. I would appreciate any advice.

Regards, Jim

Hi,

On Thunderbird 140.4.0esr (64-bit) and on 144.0.1 (64-bit) both WIN11 I have this problem since yesterday:

New message Signature is shown

I add the To: To: xyz@com.com

Signature disappears, mail is sent and received without signature

The signature which I use "since many years" is HTML

As you know there has been an update on WIN11 yesterday...

Any hints?

Thanks for your time

Bob

Sometime ago I must have made a typo when entering my email address into a pop-up window in Firefox. Firefox continues to find and use this wrong address in pre-fills but I can't find anyway to correct it. I've worked through Settings/Privacy & Security with no luck. Can someone help please? (Windows 10 Firefox 145.02)

Since update to version 145.0 I cannot send messages, when sending I get this message "Sending of the message failed. An error occurred while sending mail. The mail server responded: <*******@shaw.ca> sender rejected AUP#POL. Please verify that your email address is correct in your account settings and try again". Nothing has changed with account settings. Same problem on another machine that updated to 145.0. Any ideas what is broken?

This just started happening a couple of days ago (after I upgraded to TB 140.5.0esr on a Mac, in case that's relevant).

Every time I type the word "address" in an email, TB changes it to my home address.

Anybody know why this started? And what can I do to turn it off?

Thanks Clint

I can't seem to locate how to activate the microphone in the AI sidebar. I have Gemini selected, and when I hit the microphone to dictate I get the following message.. Unable to access the microphone. Please check settings.

I looked through Firefox settings and my laptop's but I don't see where it is turned off or asking for activation.'

Tom Z.

HI just updated to 140.5.0esr (64-bit) Now all I can see is my inbox and deleted. No Sent or any of the other many folders I could see 5 mins ago ☹️. The server has them all though Some help welcomed!

I keep getting the sign in request (photo 1) and when I click the next button I get (photo 2), I have no idea what has changed or what I can do to stop it. I would be grateful of any help.

I've been using Thunderbird to access my Comcast email for two years now, without problems. Except yesterday & today, when I've been unable to send or receive emails, for no apparent reason. Yet, when I connect to my Comcast/Xfinity email via the Comcast browser website, sending and receiving of email works fine. This access problem began yesterday, 10/14/2025.

Same email address I've been using for about 20 years now, and same password. I made no changes to my Thunderbird or Comcast settings. Sending a test email to myself via the Comcast email website works fine. Clicking on the "Get Messages" icon in Thunderbird results in no action whatsoever. Sending a test message to myself in Thunderbird results in about a 40 second delay (usually it's 10 seconds), and then the error message "Login to server smtp.comcast.net with username don-peters@comcast.net failed." It then asks if I want to try again, but if I agree, the same error results. But there is also the option of "Enter new password". Click on that and the same error results, without even asking for a new password. But my password is OK, as evidenced by my Thunderbird settings and being able to log into Comcast browser email.

Yes, I've spent hours on the phone with Comcast on this issue, but they were of no help. One agent claimed that the issue was with Thunderbird, not Comcast, as its webmail worked fine. Two years ago, I had a similar problem I spent hours trying to solve. It turned out the problem then was due to Microsoft Outlook on my PC regularly trying to log into Comcast to ALSO download my email - BUT using the wrong password. Comcast interpreted these multiple failed login attempts as scammer attempts, and blocked ALL email logins from my PC. I fixed the problem by shutting down Outlook. But when I just spoke to Comcast they said the current problem was NOT due to my account getting blocked by them. But they couldn't give a reason for the blockage.

So, I now believe the problem lies with BOTH Thunderbird and Comcast. First of all, Comcast is somehow blocking my Thunderbird access attempts. But Thunderbird is also at fault for not reporting a SPECIFIC email login problem, so that we can address it - and fix it. If Thunderbird can be more specific as to why login attempts are failing, I can get back to them with the evidence - and hopefully solve the problem.

I've been using Thunderbird for about 30 years now, and I hate to give it up. But if this continues, I'll be forced to abandon Thunderbird.

Hi, Since the last update for Mozilla on the laptop (updated on 6/Oct/2025 - version 143.0.4 (64-bit)), all the shortcuts to websites in Firefox homepage I had pinned have disappeared. Also I can't add new shortcuts. I already have shortcuts enabled in Settings>Home>Firefox Home Content>Shortcuts.

Does anyone know how to solve this?

Kind regards.

Bárbara O.

При заходе на сайте ya.ru и если на нём имеется строка с видео или поиск с алисой, то начинаются сильные фризы. Это ошибка именно в firefox 142, проверенно.

I have tried using the troubleshooting guide suggestions without success. The email is not on the server as verified by webmail, but still resides in my local inbox. Can I manually access the database offline and delete this email? I have two other gmail accounts that are part of my Thunderbird email client version 140.5.0esr (32-bit).

I have an website which I prior to this error message have visited many times on Firefox and had no problems. Recently though around two days ago I noticed that I couldn't get in and was met with the following message "Warning: Potential Security Risk Ahead". I can't bypass it apparently and I really need to be able to access this site as it's a University site.

I can access the site on other browsers such as Chrome and Edge but I use Firefox as my default browser and I'd like to keep it that way. I'd appreciate any help I can get.

Said link: https://canvas.gu.se/

When i try to insert a screenshot through the clipboard on google or yandex image search, the original image is corrupted. Even i try to upload an image via classic upload-button the same problem reproduise. On other sites there is no similar problem, as well as trying to insert the same image but inside the application windows.

In attachement: yandex/google and default image i was trying to upload.

Installed on android phone, imported account configurations using the the bar code method. Gmail accounts all good, but Microsoft accounts all fail. Multiple reinstallations have the same outcome.

The failure occurs at Passkey generation all with the same message "We're unable to complete your request server_error: The contextID supplied in the request did not have a matching cookie" or "Something went wrong trying to create a passkey. Please try again." It uses Brave Browser when doing this.

Any ideas on how to progress?

Thanks