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Hi Folks, I use, as do others I know, Thunderbird for Android. Recently it has decided that the SSL Certificate it accepts for fetching emails is not valid for sending and requires you to accept and make an exception for the certificate. Has anyone else found this? I have tested the certificate, provided by Lets Encrypt, on several servers all claiming SMTP, POP3 an IMAP offer valid certificates. Yet Thunderbird still claims it is a security threat. Can omeone off an answer please? I am currently helping others accept the certificate.

Thunderbird ofr Android is V18.0

regards Anthony

Hello,

I have been testing all browsers I use (Firefox, Chrome, Edge) on Cloudflare Post-Quantum Key Agreement to verify PQC support. They all support the X25519MLKEM768 hybrid scheme (i.e. Cloudflare web page returns "You are using X25519MLKEM768 which is post-quantum secure").

The issue: When I run the test in Firefox multiple times by doing repeated hard refreshes (Ctrl+Shift+R), quite often the result is "You are using X25519 which is not post-quantum secure". Sometimes the very first run after opening Firefox gives the X25519 (failing) result. "Often" varies. Sometimes it's around 10 fails out of 50 tests, other times it's 1 out of 50. It seems random.

I have read that sometimes networking equipment or even ISPs can be the cause of PQC requests falling back to non-PQC due to the long keys in PQC, but I do not see this intermittent issue with Chrome or Edge on the same computer/network/ISP as Firefox. I have not seen a single failure so far on those two browsers. The only variable I am aware of is the web browser.

I also tried connecting to a cellular hotspot as well as disabling my Norton 360 firewall and the results are the same as above.

Looking for help to resolve this issue. Thanks.

For the past few days almost every site I try to visit gets the error:

Secure Connection Failed An error occurred during a connection to.... SSL received a record that exceeded the maximum permissible length. Error code: SSL_ERROR_RX_RECORD_TOO_LONG

this has happened on and off in the past for one or two sites but usually fixes itself within a day or less but this time it's been days. I tried everything I've seen online: -Try without add ons, - I am using 'system settings' proxy, -Followed an 8-yr-old suggestion of switching security.tls.version.max from 4 to 3 -My AV doesn't have HTTPS scanning that I can disable -It doesn't allow me to toggle the 'enhanced tracking is on' in the address bar -I've tried adding a site as an exception to DNS over HTTPS and turning Enable DNS over HTTPS off

Nothing has helped. These are all sites I've used in the past. I am using Nightly v150 at the moment but obviously same situation with FF or R3dfox.

If anyone can suggest how to bypass this so I don't have to use Edge/Chrome/Supermium (which all display these sites without issue) I'd appreciate it so much!

(*I'm looking for help with THIS issue on a W7 laptop, not about whether I should upgrade the OS.)

Thanks.

OS: GNU/Linux Thunderbird Desktop

Is it possible to set up a TLS client certificate for authentication with SMTP, as it is with IMAP?

It works fine on the K-9 Android client for both IMAP and SMTP.

Is there a reason why this hasn't yet been added as an authentication method for SMTP?

Thank you!

Best Regards

Every time I log in and then every so often afterwards I get the pop up - you are about to override how Thunderbird identifies this site- for a now deleted mail.co.uk account. I have tried all the fixes suggested by Google but it still keeps happening and is driving me mad. It tells me the certificate is outdated or invalid and asks to confirm to permanently store the exception but just keeps coming back every time I click on confirm, it only goes away if I click cancel but then keeps coming abck.

Hallo, my setup is some server (keycloak) with mTLS needing keypairs just for allowance for the machines in the enterprise. But as far as i know, i need to setup personal keypairs for the users, not just the machines. How do i push a ".p12" keypair into the browsers trust stores? Is there a way via GPOs? As far as i have read the https://firefox-admin-docs.mozilla.org/reference/policies/, there is no support for ".p12" files?

The only way i got told from AI is via a script. If i could just stuff that ".p12" file into some place in the GPO, i would be perfectly happy... (?)

I would like to understand how DNS over HTTPS impacts browsing speed and privacy in Firefox.

Details: Hello everyone,

I am currently exploring Firefox privacy and network settings, especially DNS over HTTPS (DoH). I noticed that enabling this feature slightly changes website loading behavior on some networks.

I would like to ask:

Does DNS over HTTPS introduce additional latency? Are there performance differences between providers? Can corporate or public Wi-Fi networks interfere with DoH requests? Is there a recommended configuration for balancing privacy and performance?

I’m interested in both technical explanations and real-world experiences from Firefox users.

Thank you.

Hi, I'm using a policie file to force a family-dns. Ive written the current code down below. Unfortunately this leaves the "manage exeption"-button open, where its possible to simply bypass the block for a specific site. Is there a way to lock this button in the policie file? Thank you very much. {

 "policies": {
   "DNSOverHTTPS": {
     "Enabled": true,
     "Locked": true,
     "ProviderURL": "https://doh16.jusprogdns.com/dns-query"
   },
   "Preferences": {
     "network.trr.mode": {
       "Value": 3,
       "Status": "locked"
     }
   }
 }

}

Server Posteingang IMAP (empfohlen) imap.vodafonemail.de Ports für Posteingang IMAP SSL: 993 / TLS: 143

Server Postausgang SMTP smtp.vodafonemail.de Ports für Postausgang SSL: 465 / TLS: 25 oder 587

I have tried using s/mime encrytpion for the first time. I have created 3 different accounts using the same CA on 3 different devices. All three can communicate with each other using the s/mine encryption. I used multiple methods - sending a signed email first and then encrypted+signed, creating a .pem file with public key - importing it in Manage certificates/people and sending an encrypted+signed email. Sending an encrypted email from-to the same address also works. What I can't seem to be able to do is use any other public keys. I have a list of companies and their keys, but whether I use a file downloaded from their site or copy the key to txt and then make a .pem file out of it, as I did with my addresses, I can't send an email that is both encrypted and signed. I get "end-to-end encryption requires resolving certificate issues for ..." and the recipient status "not found". They specifically don't want to send a signature first and then encrypted+signed, and I am stuck trying to figure out what I am doing wrong. Any help is greatly appreciated.

When adding a new email account, the built-in web browser launches and displays the OAuth screen. To verify the security of the destination site, I want to click the green lock icon in the URL bar to check the details, but I can’t click it.

Does a green lock icon mean a secure connection has been established?

Using FF 140.10.1 esr on a windows pc I noticed (probably long after the fact and numerous updates) that there's no longer https:// in the address bar. Having some recent issues with security made me look for this.

When I switched to Edge, the https:// was in the adddresses I was using. There is a lock symbol, but the locks seem to change in their appearance from one browser or website to the next.

Was this verification sign removed and, if so, why?  

Thank you.

Every time I launch Thunderbird Beta 151.0b1 on Arch Linux, I immediately get a notification saying "The certificate for imap.gmail.com does not come from a trusted source." If I click through to the exception dialog, it shows "No Information Available / Unable to obtain identification status for this site" — it can't even fetch the certificate to show me what's wrong with it. The error only appears on launch and doesn't come back. Mail sends and receives fine.

From the terminal, openssl connects to imap.gmail.com:993 without any issue (Verify return code: 0, TLS 1.3, X25519MLKEM768). No antivirus, no VPN, no TLS-intercepting software. NSS 3.123.

Has anyone else seen this? Is this a known Beta issue?

Dear all,

When receiving signed AND encrypted mails from an Outlook-account I get the exclamation sign for the signature.

The message is (German) : "Digitale Signatur ist ungültig Diese Nachricht enthält eine digitale Signatur, die aber ungültig ist. Die Nachricht wurde mit einer Verschlüsselungsstärke signiert, die von dieser Version Ihrer Software nicht unterstützt wird. Signiert von...."

I already did all standard checks (trusted, new hash algorithm and so on),

Now I would like to know the EXACT reason why Thunderbird is not accepting the digital signature. How can I accomplish this?

THX in advance and best regards!

2026-04-25 SAT 14:45 BST I have boujht a DigiCert S/MIME Class 1 certificate from thesslstore, but I have not yet got it. They sent me 3 .crt files, but I have not understood how to use them. I hope someone can explain the problem and/or suggest what I can do about it please ? I do not remember having this sort of problem in previous years.

Am receiving a message reading-

The certificate for imap.gmail.com does not come from a trusted source.

Recently I set up mTLS on my admin endpoint. I tried entering it as an API on the other website, and in Firefox it wouldn't work. But if I'd try to access endpoint directly it would work, and even save my certificate choice. In Chrome, everything works just fine with both direct and API access. It is not a problem of a website, nor the problem of the OPTIONS preflight, since both of those are configured correctly on my nginx.