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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've been using Thunderbird on Windows 10 since last year sometime. Currently I'm on version 151.0.1.

I've 4 x mailboxes here and since yesterday, 3 of them show me an unusual message when checking for emails. I tried attaching a screenshot but although the screenshot uploaded, I couldn't find a way to insert it here. But the message says Unable to write the email to the mailbox and asks me to check if I've write privileges (which I have) and to cheek the available disk space.(currently 101GB free).

The message is happening 2 or 3 times each day and lasts for about half an hour, then everything works fine again. Has anyone else seen this??

Hello, Since this morning after an update of firefox the history is lost and my personal bar where I stored my bookmarks is empty now after applying version 155.0.1 the problem is still alive Help Please

Hello,

I recently opened Firefox and noticed that all my data (bookmarks, saved passwords, and history) is completely gone. I didn't make any changes or delete anything myself.

Could you please help me understand what happened and how I can recover my lost data?

Thank you.

I'm not sure how long this has been happening (maybe at least a month), but my browsing history isn't syncing properly between my desktop and phone. Previously, my desktop history was syncing to my phone, but not vice-versa. Bookmarks, passwords and tabs are syncing perfectly fine. I've tried enabling/disabling sync settings and signing out and in again and now my phone history is syncing to my desktop, but my desktop history has stopped syncing to my phone. While having the full browsing history on my desktop is preferable, it would be ideal for it to show up on both my desktop and phone.

Здравствуйте! Перестал работать встроенный VPN в баузере. До этого все исправно работало. При попытке включить, просит войти в аккаунт. После входа в аккаунт открывается новая вкладка, пишет, что удалось войти, однако сам VPN не включается

The Smart Window feature caused CPU usage and memory to max out. Disabled it as soon as I could find the setting to do so (Settings/AI Controls and BLOCK "Smart Window") and overload disappeared immediately. Everything is working fine now. What a disaster! Also did not find the interface terribly impressive or informative. Quite the opposite: It was almost deliberately vague and not at all intuitive.

Contrary to the claim that "Smart Window automatically groups related tabs, so everything has its place and what you need is easy to find" it just just described each of my open tabs (despite several related tabs being right next to each other) instead of supposedly grouping them by subject matter. That's basically useless -- I can see that for myself. Definitely not ready for Primetime.

Windows 10 Home, Firefox Version 155.0.1 (64-bit), Dell Inspiron 15 3000, installed RAM 8.00 GB, Storage 119 GB

Yes, I've been contemplating adding memory and/or buying a new laptop. But a new feature shouldn't totally freak out my system without some sort of appropriate warning about memory prerequisites, etc.

For some reason, my Gmail page doesn't show the icons on top at all. Like the archive, mark as read, and the others on top of the mailbox contents. They show up on both Chrome and Edge, so this seems to be a Firefox problem.

Computer being used with issue: HP ProDesk 600 G2 DM (Windows 10, 16GB RAM) So can this be fixed or should I just use my phone for Gmail?

How can I stop Firefox from automatic granting sites cross-site cookie permissions (see screenshot)? The problem is that the cross-site cookie(s) granted for a site more often than not is completely unrelated to that site. This problem is very frustrating.

I have tried changing several settings in Tracking Protection but nothing has stopped Firefox from auto-granting these permissions. I have for example turned off "Fix major site issues (recommended)" but it has not changed this behavior.

Thankful for any help.

Latest Stable Firefox, windows, over 4000 tabs. Overall Firefox works great for me. but when I restart it to install the latest versions etc, it only restores one active/loaded tab per window. Rest are restored, but in a closed/unloaded state. I usually have 5-20 open tabs per window, and hundreds more unloaded, it's how I work. How on earth can I get it to restore all the open/loaded tabs as they were, not in the unloaded state they default to?

Issue still occurs in a new install with no addons, default settings, under 30 tabs etc. Ditto Win 10 or 11.

Also, how on earth can I get official Mozzilla pages to use Dark Mode??

On Thursday 3rd September 2026 Firefox stopped working. I tried lots of things to get it to work to no avail. Today, 8th September 2026, I had already deleted the Firefox that was already on my PC so I downloaded a fresh copy from the Firefox website and installed it. It ran perfectly for about 30 minutes then I shut it down. 5 Minutes later, a Firefox crash report appeared which I duly sent of. Checking Event Manager a string of error messages saying the same thing, Its the XUL.DLL file that keep crashing! This was the same file that caused the failure last week. I had made sure that XUL.DLL was not on the pc when I downloaded Firefox today. When I click on the Firefox icon it open but stays on a black lower half of the screen and boxes at the top, white lined but black and transparent lines moving left to right across them, eventually it fails and closes, after a few minutes it send the crash report. Its a shame because I have used Firefox for many, many years and now having to use Edge!!!!

I installed a Mozilla/FF GMail Notifier App. I tho't that I removed it as I no longer needed it. It still Notifies me; annoying. But it's not in my Extension List to Remove again if need be??? How can a hidden/invisible App be still operating, that is supposed to be Removed?

Since Mozilla/FF has no option to Delete a Question, I found the answer to the above posted. MY error: It was a Google Linked App, not the one I Removed which did indeed become Removed. Sigh!

Since the last update 155.01 I can't use Firefox as it freezes and hangs after 3 - 10 seconds. On Windows 10 , 64 bit. There seems a bug with the last update for Windows 10 users

Crash report: https://crash-stats.mozilla.org/report/index/c0455e29-69e9-4030-8b03-fdf430260909

Not sure the crash report is related to the issue.

The same issue happens to all of my 3 Windows 10 PCs since the update from today.

I have uninstalled Firefox and downloaded again, but same issue happens again.

I cleared the cache also but to no avail

How can I use Firefox again?

Hi Mozilla Support Team,

We are experiencing a minor layout rendering issue on our online booking platform bookbustour when accessed via Firefox for Desktop.

Are there any specific Firefox CSS compatibility rules or extension settings we should adjust to optimize user performance?

Thanks for your assistance!