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My business has two domains. I can send email to a Gmail account holder using the primary domain with no issues. But amy emails from what I call the "secondary" domain below are treated as spam. This occurs with two different email addresses using the secondary domain.

Both domains are hosted with Bluehost. Exhaustive research has revealed the following:

• Settings in Thunderbird are exactly the same, e.g. ports, security, SSL/TLS, etc. for each domain.
• There is no subject line or content that could possibly be regarded as spam.
• MXToolbox indicates that the secondary domain is not on any blacklist.
• Extended support via Bluehost reveals that SPF, DKIM, and DMARC records are all correct.
• Email sent to a Gmail account using the CPanel (Roundcube) is not flagged as spam. Only emails sent via Thunderbird are flagged.
• Emails sent to a Gmail account from the secondary domain using my mobile phone, but still on the same network/IP address, are not flagged as spam.
• If I first send an email to one of the secondary domain emails FROM Gmail, then reply to it, the reply is not flagged as spam.

After many hours of head scratching (and later, head banging), I am pretty much at my wit's end with this problem. I'm an electronic engineer but this one is definitely out of my wheelhouse. Any help would most certainly be appreciated!

Thanks in advance, Don

I just downloaded your app (thunderbird) to download some important emails for my lawyer about my SSDI case.

I moved all of the ones I needed to a folder of their own.

I went into your app, found them and apparently clicked something that made them all disappear, it was not "delete" or the trashcan icon.

I've googled and everything I read tells me to go to the trash folder. I do not have a trashcan folder.

Please help.

[6/12/26, 10:49:22 PM GMT-4] Applied filter "Blocked Sender List" to message from The Home Depot® Consumer Credit Card <citi@info15.citi.com> - James, Don’t forget to use this special offer to get your Summer projects going! 🌼🌺 at 6/12/26, 10:02:27 PM GMT-4 deleted

[6/12/26, 10:49:22 PM GMT-4] Filter action failed: "Move failed" with error code=0x8000FFFF while attempting: Applied filter "Blocked Sender List" to message from The Home Depot® Consumer Credit Card <citi@info15.citi.com> - James, Don’t forget to use this special offer to get your Summer projects going! 🌼🌺 at 6/12/26, 10:02:27 PM GMT-4 deleted

The sent message is deleted but I get Filter action Failed.

Since yesterday (27 Apr 2026) any and all mail that comes into Thunderbird gets marked as SPAM. I searched online and found people saying that I could reset the junk training filter, so I did this, but incoming mail was still marked as spam. The next suggestion was to delete the training.dat file. Did that, restarted Thunderbird and incoming messages are still marked as spam. The last suggestion was to turn off adaptive junk mail controls. Didn't want to do that because I assumed that it would let spam through. Nope. Turned it off, restarted Thunderbird and two emails from my work came in and got flagged.

I'm running version 140.10.0esr (64-bit) on Windows 11. I am using IMAP to connect to the mail server but it's not running any spam detection software (like Spamassassin). I know this because it's my server and even if it was, no updates have been preformed since the first of this month and this just started happening yesterday. Combine this with the bug that Thunderbird notifies me of incoming mail, even if it's spam (didn't post about this because there are plenty going back a couple of years), is starting to make me look for an alternative.

A category (Daily Brain something) of emails that are clearly spam (you even think they are spam) are landing in my Inbox every day. I have my email set to not allow emails from any addresses that aren't in my book. If I follow their 'unsubscribe' link, I just get more of them. This is the latest one: ar849137@ocotille.com with a Reply To address of: 3527_rep_Y2pnZGVzaWduc0BlYXJ0aGxpbmsubmV0@ocotille.com Every one is different. Why are these getting through? Thanks Cary

I recently noticed that my Thunderbird has two identical Spam folders. I deleted Thunderbird from my computer and reinstalled it but the two Spam folders are still there. When I right click either one there is no Delete option.

Guten Tag,

Ich hoffe Ihr könnt mir helfen.

Ich benutze Thundebird das erste mal und würde gerne wissen wo meine gelöschten Mails hin verschoben werden wenn wie auf dem angehängten Bild keine Einstellung vorgenommen wurde standardmäßig. Werden die Mails dann direkt gelöscht aus der kompletten Mail-Adresse oder bleiben diese irgendwo gespeichert?

Die Gelöschten Mails sind im Mail Konto nicht mehr auffindbar.

Viele Grüße

I have 6 email accounts linked to Thunderbird. I noticed today on one of the accounts, along with inbox, drafts, sent, etc., there is now a spam icon. I didn't change any settings or even look at that email account today. This is the only account with that icon and it won't allow me to delete it. All settings between all accounts are the same, just this dang spam fire icon that I can't delete

I've been using Thunderbird for a few months now and I have been marking email as "spam" or as "not spam" but I am finding that a lot of addresses that I mark as "not spam" still end up in my spam folder, even after marking them several times.

What I have been doing is restoring the email that I want to read back to the inbox and marking it again as "not spam". Some email that I mark as spam does get moved to the spam folder, which is fine.

Is this was happens for some considerable time or am I getting something wrong?

I recently upgraded to TB 128.14 Oesr (64, Win 10). I’m a bit conservative about upgrading anything – as upgrades often waste a lot of time – if not risk justified.

Basically, If it’s workin’ well enough (cost vs benefit) …… well … “don’t fix it” – even though … “if it ain’t broke, doesn’t mean it isn’t sub-optimal”. Here, it seemed worth the risk.

My prior TB version – nope, I don’t remember which it was (is that in a log?) incorrectly identified bookoo normal e-messages as “junk” (junk filter deactivated) wasting a LOT of my time to move them back to the “indox”.

It also – CORRECTLY ID’ed – a big lot of data sucking spam as “junk” (junk filter still deactivated) for my PUBLIC e-address (expected spam magnet) – alerting me of the quantity of (expected) spam I was actually getting (my free Omaha steaks are on the way).

After upgrading (to TB 128.14) I don’t get any, well much of that spam any more (got a couple today) – hurrah (maybe)!! I don’t see it any more. It is gone completely (mostly, ostensibly) and the problem is – I do want to SEE it – all of it – in a “spam folder / directory” nd not in trash– wherever it is – to make sure it is NOT mis-ID’ed as spam – when actually an important message maybe telling me I’ve won the FIFA email prize!

So … “the game is a’foot! Holmes! How can I track down that missing spam – to see ALL of it – to verify it’s identity?

I suspect my hosting company – Hostinger – may be involved – as I did verify, previously, with my previous TB version – that they COULD see into my TB account structure. Can’t find it now, but previous did see MY TB account named “Aviation”. They, Hostinger, said THEY aren’t “moving” anything anywhere – not into “Junk”, anyway. Are they lying (as popular as that has become recently)?

I’m not smart enough to understand DKIM (though I could get that way) just want to see ALL email sent to ALL my e-addresses that didn’t get there – wherever it is (not immediately, I would hope)!

Merci,

Dru

Just recently, some of the emails I receive are full of messages in red next to almost every line of the email saying that things like "Likely fraud detected" or "Do not trust this website." There is no indication as to what program is creating all these warnings. I have tried to turn off anything I can find in Thunderbird's security settings to no avail. The main source of emails with these warnings is "Beermenus.com" which I have been receiving for quite awhile before this started. Any ideas on what to do

Good morning.

A few days ago the "Junk" folders in my Thunderbird accounts, without any action on my part, were suddenly renamed as "Spam" folders.

Anyone know why this happened?

Thanks

Despite my marking messages several times as NOT spam, Thunderbird keeps on and on RE-marking them as spam. And the mails are coming from one of my own addresses, and they ARE in my address book!!!!!

There seems no way that I can stop the beast from misbehaving.