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Continuation of my prior post: https://support.mozilla.org/en-US/questions/1516342

Thunderbird has a routine problem with being unable to log into various mail servers. I have four accounts and they all seem to share this problem.

Most recent update: I've tested this in Windows Safe Mode, and the problem has not appeared. Since I can't do any useful work in Safe Mode, it's hard to give it a thorough test, but so far so good. Also, I have removed AVG antivirus because it was redundant. I have seen no improvement since it was removed.

Can this problem be resolved?

Hello everyone,

I keep having the issue that on some websites, a whole list of cross-site cookies is displayed when i click the icon to the left of the address bar. "These parties can use cross-site cookies and site data while you are on this site."

Especially Google (I am not logged into a Google account) lists many different sites here. I can then click on "Allowed X" - but after a few days, the entry appears again without me being asked!

Under "Privacy & Security" I am using the Standard level. It says there: "Firefox blocks the following: (...) Cross-site cookies in all windows (...)" So why are some still being allowed? How can I generally prohibit them except for those I manually allow? The five levels for cookie handling under "Custom" are unfortunately not very self-explanatory, and I can’t find any whitelist option there either.

Thanks for any advice! Best regards, Martin

I am setting up Thunderbird on a Win10 machine, and am having a lot of trouble adding accounts that I did not have on the two Win11 machines I have set the same accounts up on.

When adding my 2 GMail accounts, after clicking "Allow" on the OAuth popup the button would go grey the window would stay open and not close, and the account would not be added.

Changing the general.useragent.compatMode.firefox option to TRUE allowed me to progress and finally add those accounts.

I am now having the same trouble with my @hotmail.com account. When I add the account, the dark blue OAuth window pops up, but is completely empty, and there is nothing more I can do.

Things I have tried

• Reverting the above config change
• Checking that cookies and JavaScript are enabled
• Checking there is no saved password
• Used both the Account Hub and the default dialog, with the same effect.

Thanks in advance!

Today, I once again had to refresh Firefox Due to my eBay page being rehashed and not usable, but I forgot about my Facebook and after the refresh found I have now lost almost six months of chat history (most recent of which is very important to me), and I just can;t find a way to recover it. Please advise me what to do. Kind regards

Several days ago Firefox deleted all of my saved passwords. When I built up a new list of saved Passwords, they are all deleted and gone the next day. Why is Firefox doing this?

Hi,

I’m experiencing an issue with my website Fixit Home ([[Interior design and fitout company|https://fixithome.ae]]) ). Certain pages and elements, including images, navigation, and layout, are not rendering correctly in Firefox, even though they work fine in other browsers like Chrome and Edge.

I’ve checked:

The website code is valid and loads without errors in other browsers

SSL certificate is active and pages are secure

JavaScript and CSS files are loading correctly

Could this be a Firefox-specific compatibility issue, or something related to caching, security settings, or mixed content? I’d appreciate guidance on how to debug and fix this problem so my site works consistently for Firefox users.

Thank you!

Hi I keep getting the message "Unable to connect to your IMAP server". I have reduced the number of 'server connections to cache' from the default 5 down to 1. Thanks

I have never deleted so many emails at one time, around 500. Did I exceed the limits of Thunderbird? I cannot log on. Cannot see new emails. I have been on emailsrvr.com and did verify my passwords. Thank You

My Policies.Json can only block 1000 websites. Nothing after the 1000th entry is blocked. Is there a way to remove this limit?

Firefox 150 on Windows

Thank you

The email address box does not accept the email address and comes up with an error message. The only way to send an email is to use a different browser ie Google. Emails are still received as normal on Firefox / BT mail

В полученном письме с почты THE AHMAD TEA STORIES d.gorshunova@sdc-foods.ru, у меня не отображаются картинки - показывает значок разбитого изображения в верхнем левом углу. От других адресатов картинки загружаются. И в других браузерах все картинки с этой почты показывает. Пожалуйста, почините!

i had multiple tabs set up in multiple groups and i used yo restore these every day when i rebooted every morning and all that is lost to me now. i can see that the groups are there but can no longer use them. how can i uninstall mozilla firefox

Can get(POP3), but can not send emails to a newly created personal outlook.com account.

the following error occurs when trying to send mail: Unable to authenticate to Outgoing server (SMTP) . Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)

all my setting are correct per thunderbird and microsoft:

  (smtp-mail.outlook.com, port 587,  STARTTLS, OAUTH2, xxxxx@outlook.com)

thunderbird error log file contains the following: . . . mailnews.smtp: S: 535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information. [CH5P220CA0005.NAMP220.PROD.OUTLOOK.COM 2026-02-28T23:29:21.878Z 08DE7703D4D1982A]

SmtpClient.sys.mjs:452:17 mailnews.smtp: Command failed: 535 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information. [CH5P220CA0005.NAMP220.PROD.OUTLOOK.COM 2026-02-28T23:29:21.878Z 08DE7703D4D1982A]; currentAction=_actionAUTH_XOAUTH2 SmtpClient.sys.mjs:578:19 mailnews.smtp: Error during AUTH XOAUTH2, sending empty response . . .

Based on my understanding its seems thunderbird is using SMTP AUTH instead of OAUTH2 as required for newer personal outlook.com accounts. Is my assessment correct? If so, is there a fix?

Since Firefox updated to version 148.0 it has broken my ability to download any extension and I get that Installation aborted message for any extension I try to download.

It also broke my ad blocker, ublock origin, when it updated to 148.0