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I was working with thunderbird today. Was in a specific email folder I had named "reference" that I use to store various emails, probably around 50 emails in there. Suddenly they all deleted from the folder as I was watching the screen. Checked spam/trash folders and nothing. Also logged into my webmail provider and nothing there either. Any idea what could have happened here? They just seem to have literally vanished. Have used Thunderbird a number of years and never experienced anything like this.

When I want to send a message (Thunderbird)I receive this message since 10 days (about..): "Clienthost rejected by spamhaus for spamming issues". see htps://check.spamhaus.org/query/ip/37.66.26.22 for further information I can use successfully WEBMAIL Can you explain me what is it? Thank you

I can't log in after changing my email password. My email address is [edited]@telia.com. I can log in with my new password using Telia Webmail. I have been in contact with Telia and they refer you. Best regards Anita Bodin

the Thunderbird inbox does not display received emails and does not display new emails.My web host provider,Hostgator, has all the old emails and is receiving new ones. so they are in their files. So the problem is with thunderbird. I have consulted your support and forums, tried troubleshoot mode... When I right-clicked on the input file and clicked on repair the display went blank and the emails vanished....also at midnight

on 1/16/26 I no longer receiving new emails.

your help will be appreciated

Lance

Some months ago I received an email, but the body of the email was a picture (jpg) from my computer. The sender definitely does not have the image. The content from the sender is missing, and my image is in the body of the email and as an attachment.

This has happened a handful of times over the past 6-9 months, with the same image showing up in emails from various unrelated senders.

I just received an email from my partner who sent me an email with a screenshot attached, but instead of receiving what he sent, I've got an email with my image that randomly shows up in my inbox.

A few days ago it happened, but when I restarted my computer, the unwanted image was no longer present, and the actual email content was visible.

Restarting my computer has not resolved this particular instance.

Does anyone know why Thunderbird is in love with this one image of mine and why it keeps showing up in my inbox in emails from other people?

I am experiencing persistent issues configuring a custom-domain email account in Mozilla Thunderbird, while the same account works correctly in Outlook and in webmail.

Environment:

Email client: Mozilla Thunderbird (latest version)

OS: Windows

Mail hosting: Antagonist / DirectAdmin (shared hosting)

Domain: s23k.com

Email address: jean-paul.sablerolle@s23k.com

Incoming mail (POP):

Server: mail.s23k.com

Port: 995

Security: SSL/TLS

Authentication: normal password POP connection works without errors.

Outgoing mail (SMTP):

Server: mail.s23k.com

Ports tested: 465 (SSL/TLS), 587 (STARTTLS)

Thunderbird fails to send mail with the error:

“The requested domain name does not match the server’s certificate.”

Even after explicitly adding and permanently accepting the certificate exception, Thunderbird continues to reject the connection.

Important observations:

Webmail (Roundcube) can send mail successfully.

Microsoft Outlook can send mail successfully using the same SMTP server.

Thunderbird never completes SMTP authentication because the TLS handshake fails on hostname validation.

The certificate presented by the server appears to be issued for a different hostname than mail.s23k.com.

As a workaround, I am currently using an external SMTP server (KPN: smtp.kpnmail.nl), which works correctly in Thunderbird.

Question: Is Thunderbird intentionally stricter than Outlook regarding TLS hostname validation for SMTP, and is there any supported way to:

properly override this hostname mismatch for SMTP, or

diagnose whether this behavior is expected and unavoidable with misconfigured server certificates?

I would like to confirm whether this is expected Thunderbird behavior or if there is a configuration option I may have missed.

I am not trying to weaken security; I want to understand whether Thunderbird allows any safe override in this scenario or if the server configuration is fundamentally incompatible.

Suppose I see 10 incoming emails on my server (core.com). In thunderbird, when I click to download them, I see a message saying something like "downlaoding 10 emails". After that only 2 or 3 of them have been downloaded, the rest deleted. Help! This started happening a couple of weeks ago. I have tried downloading and re-installing Thunderbird, to no avail. Should I change my account settings?

I get this message when I try to send out emails:

Det gick inte att skicka meddelandet. Ett fel uppstod när e-post skulle skickas. Servern svarade: [M5] Your credentials have been compromised. Please change your password or contact support (2fe59c46-0669-11f1-a827-e90f2b8e16ca). Kontrollera att din e-postadress är korrekt i dina kontoinställningar och försök igen

I changed password, and it changed to this:

[R9] Your credentials have been compromised. Clean your devices from malware, change your password or contact support (4beaa535-066d-11f1-a6bf-f7376af24660).

Through my e-mail provide one.com, its working as usual. My other emails works on Thunderbird as well.

I still receive email to Thunderbird email.