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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.

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

I downloaded TB Supernova ver. 115.18.0 (32 bit) to my wife's old Gateway computer. (Win 7 Ultimate Svc Pk 1 32bit). However, after manually configuring the server settings, I get the above error message. Additional information: This old Gateway had Thunderbird on it at one time - don't know the old version. It worked, then quit after an upgrade, and I haven't been able to get it to work since. The ISP provider still has our original password, and I can log into their email server and see 81K worth of emails. I have a Toshiba laptop, also Win 7 64bit, and TB SuperNova is installed and working on it. I used the server settings from my Toshiba to manually configure TB on the Gateway... Any ideas as to what to try next? Peter

I am using internet server provider www. namespro.ca server settings for my email account set up with Thunderbird mail and the email account will not set up properly. I currently have (1) domain name "realestateX.com with www. namespro.ca and I am attempting to set the email accounts using Thunderbird Mail on a desktop CPU. The email accounts will NOT set up with ThunderBird Mail with this domain name, 'realestatex.com.' On the other hand, the same domain name email account were succcesfully set up on OUTLOOK using the same www. namespro.ca server settings with success, they work properly in and out

Back to the Desktop CPU and my Thunderbird Mail program; I have another email account set in with another domain email account realestatex.net with a completely different internet server provider www. webnames.ca and that email works fine in and out and the set up without an issue

Back to namespro.ca their server settings work fine with MS 365 OUTLOOK email set up on my DELL laptop. However the server setting from namespro.ca will not work on the desktop and laptop, The laptop set up is using a MOZILLA Thunderbird Account Hub and stated their is an "authentication error because of a policy violation relating to the refused connection from the IP" . Would namepro.ca IP connection refusing my thunderbird mail account to syne with namespro.ca? any insight would be helpful, appreciate your time

On a dual-stack network, with Windows tcpip6 ‘disabledcomponents’ parameter set to prefer IPv6, Firefox ignores this setting whenever an endpoint resolves both an IPv4 and a NAT64 address.

While monitoring traffic captured while connecting to sites in Firefox, if the initial DNS request for the site comes back with an IPv6 address only, the connection attempts from client’s IPv6 address to destination IPv6. If DNS answers come back with IPv4 and IPv6, the connection attempts IPv6 to IPv6. If DNS answers come back with IPv4 and a NAT64 address, Firefox doesn’t even attempt to connect to the NAT64 address, it immediately defaults to IPv4. I’ve tried disabling the IPv4 fallback setting which doesn’t change the behavior.

We’re running version 140.8.0esr. Is this behavior intended for Firefox? Is there a way to configure Firefox so it doesn’t ignore NAT64 addresses in dual-stack environments? The only way I found to force this was to completely disable the IPv4 stack on the client system’s NIC.

As of recent I increasingly have issues with accessing websites, those websites previously (yesterday) worked fine on Firefox. Version is 148.0 on Mac 26.3 (Apple M3 Silicon).

Now it has completely stopped working. Only websites using direct IP-address still work, all others fail with "Hmm. We’re having trouble finding that site.". Safari still opens the websites flawlessly.

Nothing has changed on the OS level or application level as no updates have been installed (no need, as everything is up to date). Antivirus is BitDefender with extension for Firefox enabled for already an extended time (year or so).

I tried disabling several dns.resolver settings as mentioned in https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can. No improvement whatsoever.

I quit firefox, removed the cache manually and restarted while starting a new test profile, so completely blank. Issue is still there.

DNS Servers on OS-level are correct.

Version 148 was installed last night evening and as such could be the reason for the failure since it is basically the only thing that changed.

I've used Thunderbird connected to comcast.net for months on a new laptop. No issues, and it worked fine - until I left my home WiFi and attempted to use WiFi from my home in France. At that point, I just got an error condition saying comcast is rejecting my login attempt.

I've worked with Comcast technical support, with no improvement. They do not seem to detect any blockage of my IP address here.

I deleted my Thunderbird account connection to comcast and tried to re-create it, but have had no success. The error condition I get is: 'Unable to log in at server. Probably wrong configuration, username or password.' I'm certain I'm using the right username and password, and I can log in to Comcast webmail using those credentials.

I've tried with VPN from my US home, VPN from France, and no VPN. I've cleared cookies and cache, and validated my attempted account settings from many messages here regarding connection to Comcast. Neither IMAP or POP3 protocols will connect. POP3 / Hostname mail.comcast.net / Port 995 / Connection security SSL/TLS / Authentication Normal password. My Comcast email account is still set to allow third party connection.

Any other approaches that might work would be appreciated.

Using latest thunderbird on desktop, if I create account, thunderbird pops up a window but the window greys out and never gives me a way to input password. There’s a url at the top but it never goes

I don't receive email on my computer in MX. I did for 2 months. Now it's stopped. I tried to change to "No Proxy" as AI advised, but that doesn't register/the computer button remains white.