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I have been using Thunderbird for ages now with no problem, but I suddenly realised that no recent emails were appearing from my Gmail account. I have tried everything suggested on line to resolve the problem, including uninstalling and reinstalling Thunderbird, and deleting and re-entering my acccount details but neither the IMAP or SMTP servers will connect to Gmail. I have reset all of the server settings on Thunderbird, and have checked that Gmail is IMAP compliant (which, apparently, is is now automatically). I have spent hours trying to sort this out and am just at the point of abandoning Thunderbird completely, but I am loathe to do so if there is a solution. The latest error message i have received is "Unable to log in at server. Probably wrong configuration, username or password" but I don't know what else I can check or change.

I received this message: Unable to connect

The connection was refused when attempting to contact localhost.

   The site could be temporarily unavailable or too busy. Try again in a few moments.
   If you are unable to load any pages, check your computer’s network connection.
   If your computer or network is protected by a firewall or proxy, make sure that Thunderbird is permitted to access the web.

I am not receiving new email. What do I need to do to get it working again?

One of my two outlook email accounts no longer appears in Thunderbird, which says it is authenticated but not connected. This happened suddenly. I can still get the messages by going onto outlook.com. How do I get it back on Thunderbird?

When in e-mail I get a message concerning not being able to connect I MAP settings as there are too many or something like that. (Message disapears quickly). It indicating that I should use advanced I MAP settings - all of which is way beyong my primative knowledge. Anyone throw any light on this regarding what and how to do or who to contact Thank you . Bernard

There are times when i am using Firefox that my PC will randomly disconnect from the internet. Sometimes it will reconnect on its own after I close Firefox. Other times I either have to restart my PC or go into Network & Internet settings and connect to my network. I am still running Window 10, free updates. Does anyone know what is causing this? It does not happen with any other browsers.

I've been using Thunderbird since it was first made available for Android, and I've used it successfully until recently. I have a new Outlook email address that I cannot sign into even though the Outlook email I have been using with Thunderbird since the beginning has never given me any issues. I get the "user authenticated but not connected" error. What can I do to resolve this issue so that I can have all my emails together in one app. Just to make things clear my old Outlook account which uses the email in writing you from connects flawlessly. It's a new one that is giving me issues. Any help would be greatly appreciated. Thank you for your time.

Firefox 147.0.4 on macOS 26.3 does not work via SOCKS proxy.

Firefox 147.0.4 on Windows 11 x64 works fine via the same intranet SOCKS proxy, with exactly the same settings.

The advantage of Firefox is its flexibility. It supports its own SOCKS proxy settings, independent of systems-wide ones. Unfortunately, it seems this Firefox feature is broken on macOS (but Windows version works perfectly).

Safari 26.3 (21623.2.7.11.6) and DuckDuckGo 1.177.0 (625) web-browsers that use system-wide macOS SOCKS proxy settings also works fine with this intranet proxy server. So it seems SOCKS proxy server itself is OK, and the problem is confined to Firefox on macOS.

Has anyone seen Firefox 147 on macOS work via SOCKS proxy? Is there a principal difference between how Firefox handles SOCKS proxy on macOS vs. Windows? What might be the best way to address the problem on macOS?

Thanks!

I’m using Thunderbird to connect my Hotmail account. The setup shows as “successfully added,” but an error message appears:

“The operation on Inbox did not succeed. The mail server for account responded: User is authenticated but not connected.”

Previously, the connection worked perfectly, but starting this week, Thunderbird can no longer access or sync the hotmail mailbox.

How to fix this problem!!???

For 2 years have been trying to get Thunderbird to access my mail from The Messaging Co. My old Win 10 laptop has no problem. My new win 11 laptop won't. I have configured the servers over and over but everytime I try to access Thunderbird I get "could not connect to mail server: the connection was refused". Who is refusing the connection? And why? I have re-downloaded Thunderbird several times but the problem persists. I am using Firefox. And using the in and out servers as per my win 10 laptop.

I am using 140 ESR version on linux with Cloudflare's DNS over HTTPS and with DOH active for some reason resolving a domain like d3oklwo3y1bx83.cloudfront.net will resolve to local host IP 127.0.0.1.

I am using firefox about:networking#dnslookuptool to test resolution of the domain d3oklwo3y1bx83.cloudfront.net Both with DOH on and off the resolution remains local host. I tried another browser on the same workstation and I was able to receive a resolution of 13.225.193.203 13.225.193.133 13.225.193.64 13.225.193.58 Why is firefox ESR not able to resolve that domain? What are causes ?

Is is firefox dnslookuptool results.

I've recently set up Thunderbird on Linux Mint 22.2 and was unable to sign into Yahoo so I tried to sign in with Firefox instead and had the same errors :-

   Something went wrong
   We could not sign you in. Try again from a different device.

OR

   We couldn’t sign you in
   Change your browser settings to continue. Try the following:
   Turn off ad blockers
   Enable JavaScript

If you still can’t sign in, try a different device.

I can sign in with Chrome without any problems on the same workstation. Firefox version :- 147.0.4 (64-bit)

   Only Extension is Privacy Badger, but this is disabled for Yahoo.com

Thunderbird version :- 148.0 (64-bit)

   No extensions - as installed from Thunderbird download site

I'm not having any issues signing into any other websites / email accounts (Google, Hotmail).

I notice on the support website :- https://support.mozilla.org/en-US/kb/thunderbird-and-yahoo it says "Starting with version 148, Thunderbird is switching to a more secure authorization protocol PKCE for Yahoo" BUT this isn't offered in the list of Authentication methods, has PKCE been delayed? Currently using OAuth2 for Thunderbird

Hi, T/bird working fine upto Thurs night Feb 26th then yesterday morning I got pop up windows asking for login credentials. Nothing had changed. Tried logging in thru them put it errored: <<

               Something went wrong

We could not sign you in. Try again from a different device. >>

I can log into my Yahoo accounts using Firefox so passwords isn't the issue

I've read thru a number of threads on here and elsewhere but no solution so far. K9 is working on my Android phone and my wife's and her T/bird is working on her PC. Just checked versions, she is on 140.8 ESR and I'm on 148.0. Both running Win 11 Pro.

Tried changing from OAuth2 to Normal, pop window asking for password but that doesn't work

Seems to me to be an issue with Ver 148.0 as my wife's working

What am I missing?

Ik krijg geen verbinding meer met mozilla thunderbird email. Google is mijn provider. Google vermeldt: server kan het verzoek niet verwerken omdat dit niet de juiste opmaak heeft. Ik heb wel mijn wachtwoord in Google verandert door Odido probleem. Ik vermoed dat dit het probleem kan zijn. Mijn vraag is of u dit op afstand kan bekijken

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

Trying to connect to my AOL mail account on a laptop w/ win 10 & thunderbird returns the message not a valid certificate. AOL support said change the password to reset the account, which I did. Now all I get is " Host contacted, sending login info " & it the server connection times out. I can log into my AOL account with firefox. Any help will be greatly appreciated !!

In Thunderbird account setup, I correctly enter my email account, name and password. I know it works because I can open my email on the Spectrum login page. I get a confirmation green box then when I press done a yellow box says unable to login at server, probably wrong configuration, username or password.