Thunderbird Community Forum

This morning I started getting this popup in lower right part of my screen every minute :

Mozilla ESR Thunderbird Connection to server inbound.att.net has been reset

It continues over and over as TB tries to get new messages.

Also, AVG Free antivirus is telling me it has identified a site certification problem. LOCATION: inbound.att.net (POP) Process: thunderbird.exe Detected by: Email Shield

In TB Help it says I'm currently on the esr uipdate channel .....whatever that means Whats the issue here? Can anyone help?

Since the recent update, 157.1, I cannot get the "Get Messages" button to work and it will not download new emails. I can download a previous version and it works just fine. I also cannot stop the auto updating function even though I check the box to not auto install.

When I attempt to send email I get the following message: Sending of the message failed. The message was not sent due to exceeding the allowed number of recipients. The server responded: Policy-SC01 You’ve reached your sending limit. Don’t worry, you can send again soon..

Greenby Support wants a screenshot of Thunderbird Outgoing Server (SMTP) which I can't find via the App menu or any other means of searching. So I do not know which version we have re your question below and I have chosen one shown at random to allow me to submit my question

TB is sending most of my email to the wrong folder. I had 21 message filters, but then I noticed that a lot of things were going to a folder named "bridge" for no apparent reason. I looked at the filter log, but there was nothing in the log for the last few months.

I did have a filter sending certain messages to the "bridge" folder, but TB is sending things there for no reason. I disabled all 21 message filters, and it is still doing it.

I have version 155.0 and I'm using Windows 11 25H2.

How can this be fixed?

The message filters simply are not working. Not only are they not directing incoming messages to the correct folders, they are also moving some messages in a folder to another folder without a rule!

I did a complete review of my message rules, cleaned them up, had some success, but the next time I opened Thundered to check email, some messages were still directed to the wrong folder. I have used Thunderbird for years, know how to use/create message rules and had no trouble prior to 155.

ALSO - tried reloading Bird 154, but it wouldn't do it because of "Profiles." Bad move there. Frankly, those multiple Profiles are a pain in the butt in Bird and Firefox, a perfect example of if ain't broke, don't fix it.

Firefox 155.0.1 Windows 10

for a week or so now, I get the following message when trying to send" Sending of the message failed. An error occurred while sending mail. The mail server responded: Transaction failed Reject due to policy restrictions. For explanation visit https://postmaster.gmx.net/en/case?c=hi&i=ip&v=149.102.242.95&r=1Mirna-1wPNAF1v2y-00h7M4. Please check the message and try again."

receives fine, will not send

My recollection is that prior to a recent automatic update to Thunderbird 140.12.1esr (64-bit) when I had a message composition window open, there were "SEND" button and possibly a "SEND LATER" button (to the left of the addressee and cc addresses in addition to the keyboard shortcuts (CTRL ENTER and CTRL SHIFT ENTER).

Following the update, there is no longer anything to the left of the addressee information. I have checked the toolbar menus, and there do not appear to be any button options. I can still send messages, but the lack of the buttons is a hindrance.

The STAT command did not succeed. Error getting message number and sizes. Mail server pop.gmail.com responded: [SYS/PERM] Your account is not enabled for POP access. Please visit your Gmail settings page and enable your account for POP access.

I'm using Thunderbird 152.0a1 (2026-04-22) on Windows 10 64 bit. When I click the "Get Messages" button or File > Get New Messages for > [my e-mail account] nothing happens. The only way I've found to check for messages manually is by closing and re-opening the program.

I used to click the incoming Email and a box was highlighted for Reply? I have no desire to move from Windows 10. Why make it annoyingly difficult for older users?

In Thunderbird 151.0.1 [64 bit] I get the following error message: Error Inbox - inbox on .....[my email address] "There is not enough disk space to download new messages. Try deleting old mail, emptying the trash folder and compacting your mail folders and then try again." I did all of that, even went into windows disk cleanup to free up more disk space. I get the same error message. I have 3 email accounts in Thunderbird, only one account has this problem. When I use Outlook express I do not get any error messages but I do get a malicious email that AVG intercepts. So how can I purge bad email from Thunderbird ? Or what else may be going on and what else could I try ? I have deleted all old emails, in Thunderbird, I routinely delete old emails. Thanks alot Sam

When all the comcast accounts migrated to yahoo, there wasn't supposed to be a change but I cannot send or receive messages through Thunderbird. I deleted my old passwords and tried to use the one that works at yahoo but it is not working.

Apparently I also have 3 thunderbirds running on my machine .  I don't know how to get rid of the old ones

I also got an error message that says 151.0.4 is not compatible with 151.0.3