Thunderbird Community Forum

I just now saw an archive folder in Thunderbird containing 45 messages that I have either deleted or were still in my .Inbox. Actually, I have never archived any message in Thunderbird. I haven't touched any of the settings to put this auto-archiving into play. I delete messages and compact folders. on a fairly regular basis to reduce the clutter. There was also a new Inbox sub-folder marked 2026 that I had not created and don"t particularly care about having. These changes are "un-arranging" my folders and messing with my system. Anybody have ideas how this happened, and how I can prevent it from happening again? Many thanks. Your help will be appreciated.

I cannot get the Subscribe function to do anything. I would like it to hide, in my Folder List, some of the extraneous folders that are present either as Mozilla defaults or AOL Mail flow-down folders.. From what I read, like a number of folks have simila or nearly similar duplicate Trash/Deleted Items, Sent/Sent Items & two labeled Drafts, albeit one's properties identify it differenet from its Drafts label as Draft (singular) while the other's properties identify it as labeled, Drafts.

For a cleaner Folder List appearance, I wish to hide the unused folders from the Foder List, I have the desired Sent, Drafts & Trash folder desitnations mapped in the TB Server settings, etc. (I assume there is only one avenue for this), thinking the unused foldes would then be available to be hidden. However, deselecting unwanted folders in Subscribe has never done anything, to any folder. When I return to the Subscribe window again, the deselected folders have been reselected.

I've seen a lot of messages here with many different suggesed remedies, but haven't found any one yet that was reported as being successful. Is there one?

Matt

I am using Thunderbird Meadow.

Is it possible to send emails without a subject, other than getting the warning dialogue box.

It would be very useful.

Thank you

I updated t the latest version of Thunderbird but since then none of my email addresses were changed with the update. Tried all the advice on line but still can't retrieve my saved email addresses from the inbox and sent box

I have used Thunderbird for years with complete success. Recently (within the past month) I have lost the ability to send (SMTP) mail and receive the following error message: "Send Message Error, Sending of the message failed. Unable to authenticate to Outgoing server (SMTP). Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)." [I just change my from address to another one going through Network Solutions and the mail sends just fine.]

Everything seems to be in order when checking my settings. I finally called Yahoo and spent an hour on the phone with them, including a supervisor (in the background) and they were unable to correct the situation. Yes, since I had called them from their tech support line (I looked it up; did not call anything sent to me) and they worked on my computer trying to fix it. They finally said it was a Thunderbird issue and said I needed to contact Thunderbird.

I am able to send from my phone (Android) using the same cox.net e-mail address. My wife is able to send from her computer using her cox.net via Thunderbird. My wife's incoming mail is IMAP while mine are all POP.

I happen to have several cox.net accounts and get the same SMTP error on all. However, all receive POP mail just fine, but see the next paragraph.

[As an aside (?), I should note that after Yahoo attempted to "fix" the problem, ALL my incoming cox.net mail comes into ALL of my cox.net accounts regardless of which one is addressed.]

I don't even know where to start at this point. Thanks for any help.

Bill

For a few weeks now, sent emails have not been appearing in the "Sent" folder. The recipient receives the email, but I have no confirmation in "Sent" that it was actually sent. It was never a problem.

Each time I open TBird, I get a message at the bottom left of the screen telling me that TBird has deleted X number of messages. I do not want TBird to ever delete any messages. How do I turn this automatic delete function off?

Bug report 15 Aug. 2026

The disappearing emails.

It took me a while to find out what was going on. My friend said some of his Sent mail was nowhere to be found. After searching for it in a 'wrong' place it does not exist. Sending to the same recipient and again it just disappears. Simplifying the mail down to just address and the word "test", it still disappears. No combination of a Thunderbird search nor an Everything search finds anything. No return error message from this provider nor the recipients.

This address is for the local electricity board, other mails to other departments

go through correctly and are found in the Sent email directory.

A careful inspection of the contact information shows this is the only department

without a "Shown Name" it only has an email address filled in.

Entering a Name for this contact solves the problem, it now shows up in the Sent

folder and is easily searchable.

I hope this explanation helps some one else with a 'Houdini' email.

My Thunderbird email account no longer lets me send out messages. I get a message error

  QUOTE____

Sending of message failed. An error occurred while sending mail. The mail server has responded. Message contains bare CR and is violating 822.bis section 2.3. Please check the message and try again.

But I am able to receive messages.

Can anyone help. Thanks in advance!!

bob.fannon

Feb 14, 2026, 13:01 CST

I have used Thunderbird for a number of years with Plusnet (using POP settings) in the UK. However, Plusnet has transferred their support to a company called Greenby who have made a hash of it and offer very poor support. So, I want to use Outlook as the mail server but I am unable to send any messages via Thunderbird to the Outlook server. I can however download messages with no problems. The error message I get is :- Sending of the message failed. Unable to authenticate to Outgoing server (SMTP) smtp.office365.com. Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)'

My default Outgoing Sever settings are :- Server Name : smtp.office365.com Port: 587 User Name: bob.fannon@outlook.com Authentication method: OAuth2 Connection Security: STARTTLS

I have tried deleting the Thunderbird account and re-creating it but still got the same result. I also tried to use my old Icloud account ( having first setup my App Specific password) but got the same result.

Little thing. None of the sections seemed appropriate. Win 11 153.0.3 (64-bit) In the left-hand panel of Calendar the top left icon of the actual calendar day/week/month matrix is supposed to take you to today (though it's not obvious by the icon which changed a few versions back). When first coming to it after a restart (hibernation mostly in my case) it doesn't move the highlighted day. I have to click first on any other day, then click the icon for it to go to today.

We are facing issues with Thunderbird mail application.

Incoming emails are not being received in Thunderbird. Thunderbird is running very slowly and frequently becomes unresponsive. Sending and receiving emails is taking a long time. We have already restarted the application and system, but the issue still persists.

Kindly check the mail server settings and Thunderbird configuration from your end and advise on the necessary action to resolve this issue as soon as possible.

Your prompt support will be highly appreciated.

We're planning to switch from Outlook to Thunderbird, but we have a hard time in harmonizing font sizes on text and signature. One of the issues is that fonts can be set to textual values tiny, small, medium, etc. w/o knowing what it corresponds to in pt. But lets explain what we tried so far: - Under Settings/ General / Language&Fonts, we defined Calibri 12 as default, what we repeated under Advanced for 'Latin' & 'Other Writing Fonts' - Under Settings / Composition, we defined Calibri / Medium for the HTML Style - The HTML-signature is defined using the Calibri 12 font But when creating a new message w/ these settings, the result is terrible as you can see in the example: disregard the fonts' color, just look at the font sizes.

Is there any simple solution?