Thunderbird Community Forum

Aloha. I'm helping a friend with setting up a new Windows 11 PC, and cannot get Thunderbird to connect to Spectrum's servers. I spent an hour on the phone with Spectrum support and they just gave up and said it must be an issue with Thunderbird. Here are the details:

- Brand new Dell 24 All-in-One EC24250 - Windows 11 25H2 plus all additional fixes. - All Dell drivers updated. - Thunderbird V155.0 64-bit

If I click on 'Get Messages' after a while I get: "Connection to server mail.twc.com timed out". I've gone into the config editor and changed mailnews.tcptimeout from 100 to 500 and still get the error.

In the Account Settings | Server Settings | Test server connection I get: An error occurred connecting to mail.twc.com:993.

I've tried this with both setting up a brand new account in Thunderbird, and also via copying the 'Thunderbird' folder from %appdata%\roaming from her old machine.

Email configuration (from Spectrum).

IMAP Settings Server name: mail.twc.com Port: 993 user name: abcd@hawaii.rr.com Connection Security: SSL/TLS Authentication method: Normal password

SMTP settings Server Name: mail.twc.com Port 587 Connection Security: STARTTLS Authentication method: Normal password

Can anyone help me troubleshoot this scenario?

Mahalo, Harry Z

Thunderbird ver 115.18.0, on a Win7 machine, upgrading not an option

When opening Thunderbird I get a sign-in message, inserting my email address and clicking the next button I get the google error message.

When I try to start Thunderbird on my Windows 11 laptop it does not start properly It is haging ond after a whike i get a message that thunderbird does not respond ("svarar inte" in swedish). Sometimes if I try to reinstall Thunderbird it starts up, But today nothing happens.

After latest update Thunderbird cant send or receive emails. My settings are correct mail.charter.net port 993 outgoing mail.charter.net port 587.

Tells me I have a server error and is constantly asking for my password. HELP!!! I have been with Thunderbird since the beginning and have sent money to the cause, and now I need your help.

Thanks, Pam

Additional details:

• Operating system: Windows (please specify your Windows version if known)
• The issue started on August 25, 2026.
• Thunderbird becomes unresponsive shortly after startup.
• A “System Integration” prompt appears before Thunderbird becomes unresponsive.
• I cannot click any buttons once Thunderbird becomes unresponsive.
• I tested both available profiles (“default” and “default-esr”) using the Profile Manager, but the same issue occurred with both profiles.
• I also started Thunderbird in Troubleshoot Mode with all add-ons disabled, but the issue still occurred.
• I can force-close Thunderbird through Windows when it becomes unresponsive.
• I have not deleted or modified any Thunderbird profile files because I want to avoid losing existing email data.
• The profile containing my email data appears to be “default-esr”.

I would appreciate any guidance on how to identify the cause of this issue and restore Thunderbird without losing my existing emails.

I don't know where to start. Ever since the update to version 154 I've been having one problem after another: switch from Comcast to Yahoo causes problems with THunderbird, slow indexing, arbitrary folders showing up in different email addresses (confuses my account with my wife's' some of that may be problems dealing with gmail issues), lost email folders after attempted repairs. Three months ago there were none of these problems. I have not yet tried switching back to the last updated version of 153, but 154 does seem to have many more problems. I've run troubleshooting.

I am not a computer expert and there is only so much time I can devote to this, but even computer repair services I've called are at a loss and very pessimistic about the ability to repair things. In all the years (over a decade) my wife and I have used Thunderbird, there have never been as many problems as have surfaced in the last two months. Maybe the best that can be done is to hope that updated versions will gradually fix these issues. I will say that my Macbook Air (M2 chip) has far more problems than my iMac (M1 chip). I have checked and rechecked all server settings (smtp and imap). Although more cumbersome, things perhaps work better if I just stick to webmail options.

When trying to open Thunderbird it does nt with the message "Thunderbird Not Responding" I try to open in Troubleshoot mode but that does not wotk either. I have to start and re start the laptop and finally after many tries it finally opens. Frustrating

All of a sudden I have to open the program twice for it to run. First time the screen opens but it is just blank and says it is not responding. So I close it and then open it again and it is fine. Anyone know why this is happening?

“My Spectrum email address is [redacted]@charter.net. Spectrum webmail can send and Thunderbird can't receive or send. The outgoing server is mobile.charter.net and the connection times out. I tested the connection from my computer and ports 587 and 465 both respond successfully. Thunderbird is set to No Proxy. when i tried to send today, it gave me this message, "Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) mobile.charter.net timed out. Try again." i contacted spectrum about this and now when i try to send, it says nothing and the message never arrives.

Cannot send or receive Emails. Seems I am off line. How to go on line? OK when I closed last night. When I go to file, offline, "work offline" check shows. I uncheck it - no change. Look again, it is checked again. Ideas?

Out of the blue Google started blocking one of my Gmail accounts on Linux Mint. It's been running fine for months. The rest run fine. It kept giving me this error message.

400. That’s an error.

The server cannot process the request because it is malformed. It should not be retried. That’s all we know.

I installed that account on my windows box with exactly the same information. I cut and pasted it in fact. It went right through with no problems.

It's one of my main accounts and it's dead in the water. I deleted it and tried to reinstall it and I have exactly the same problem. Setup information. Hit continue. "Configuration found" Click done. Goes to "Sign in to continue to Mozilla Thunder bird Email" Put in email address. Click next and I get that error message. Help?

Captain Quack.

I have settings from Greenby to set up server connections for a new account. They are validated by thunderbird but, after, entering my greenby password, generates the error, below, which greenby claims is a thunderbird problem.

"Component returned failure code: 0x804b000a (NS_ERROR_MALFORMED_URI) [nsIIOService.newURI] Show less

Component returned failure code: 0x804b000a (NS_ERROR_MALFORMED_URI) [nsIIOService.newURI]"

Now my greenby password works on their systems

Now I'm very new to Thunderbird so not familiar with the commands

Any one any ideas ?

This morning, my email Inbox is empty. I use Thunderbird for four email accounts, and three of them are fine, but the fourth one has an empty Inbox this morning. I didn't (intentionally, anyway) move the emails anywhere, and they do appear to be in the All Mail folder, so I didn't lose them entirely. But I keep my emails mostly in my Inbox and they aren't there anymore.

Any ideas what happened to make them disappear and how I can get them back to the Inbox?

Thanks!

Can't send emails on my computer on internet out of fredfam@frii.com since about 8/23/26. Couldn't solve problem. Added my Gmail account to Mozilla about 9/5/26 to keep being able to send some emails. Sending in Gmail failed since about 9/9/26. Problem somewhat corresponds to update of Mozilla 153.1.0. I still receive incoming emails on Mozilla laptop for both email addresses. On 9/13/26 all my Mozilla calendar events disappeared for several months and when I enter new events now, they disappear next time Mozilla loads. Running Windows 10, have not had such problems before. I've checked and changed Port settings many times, no result. My router provider detects no problems with internet connection. Is the OAuth process causing the issue with sending on outgoing server.

I have 2 Android phones. Both phones send and receive fredfam and gmail messages correctly between phones when having good tower contact. My gmail web browser account correctly shows send & receive. My FREDFAM web browser correctly shows send/receive messages.

My computer, Mozilla, receives messages sent by either phone for both email addresses.

I've had Mozilla software updates series 153.1 thru 153.2 from 8/23-9/2/26.

I had to use my Gmail password to enter this help system as my password for my FredFam account or password indentifying my laptop would not work to enter this help system. Something seems really messed up in my Mozilla setup/version. Thanks, Dave Freddy