An error occurred while sending mail: The mail server sent an incorrect greeting: cm5nec smtp.talktalk.net ESMTP server not available.

Email not sent and place in sent items.

Hi The error you are seeing does not come from Thunderbird. In the complicated process of email communication, Thunderbird has sent your message to your email provider. Once It sends your email to the first system in the chain of communication, Thunderbird puts a copy in the Sent folder. After that, the message is checked and processed by several other systems, on the way to the recipient. If an error occurs, the system where that happened sends an email back to the sender to let them know. Sometimes it can take 24 hours or longer for such a message to be sent back to you. In a nutshell, Thunderbird did its part in connecting to your email provider, and putting a copy in Sent. Some time after that, TalkTalk reported an error, by sending you an email. I hope this helps! Agnes

Well in the old days of Oulook Express this never happened. If an email failed to be sent for reason such as it was not authenticated by your ISP, the failure message would result in the email not being put in sent box as it was not sent. If it fails at the first stage, i.e. the smtp server used rejects it immediately, surely Thunderbird should wait for the message before putting the email in the sent items.

Thanks anyway.

There are some other help requests on this support site that seem very similar to yours, also with the TalkTalk service. https://support.mozilla.org/en-US/questions/1101658 Try contacting TalkTalk and see if there is something in your settings that needs to be changed. Agnes

I agree - if the error message comes from the sending server of your own email provider, Thunderbird should get the message that sending was unsuccessful before deciding to create a Sent copy. Usually, that is exactly what happens, but sometimes Thunderbird does not get the confirmation. To get a little more technical - Thunderbird development has included efforts to cope with email servers that don't properly complete the confirmation of a sent email. Under certain circumstances, some servers simply end the connection before completing the error or success confirmation process. When this happens, Thunderbird literally does not know whether the message went or not. Thunderbird developers had the choice of either potentially losing the outgoing message altogether, if the connection was cut off, or keeping a copy in Sent. They opted to keep a copy, even if putting it in Sent might sometimes be misleading. (See Bugzilla for details of Thunderbird development.) Best wishes, Agnes

In my case the error is immediate and stays on screen, so Thunderbird should know it an error was rendered.

I do not agree that Thunderbird developers had the choice of either potentially losing the outgoing message altogether, if the connection was cut off, or keeping a copy in Sent.

They had a better choice: putting it in outbox.

let me get this.

You click send. A sending dialog pops up saying the mail is being sent. Eventually this dialog (which has not gone anywhere, only the text changed) announced there is a sending error? You click ok and the original email is still in front of you.

Or, are you one of the old time outlook express folks (you mentioned it and reminded me of the poor implementation of send in background) that have changed the default preferences so Thunderbird works more like outlook express on sending but has no error handling for send errors.

Use the config editor to ensure the followinf user preferences are set to their default values.

mailnews.show_send_progress True
mailnews.sendInBackground False

No.

I click send. A sending dialog pops up saying the mail is being sent. I received a message there is a sending error. The original email is sent to the SEND folder. It is not in front of me. But it was not sent. If I missed the message, I would have assume it was sent.

I have not changed any default settings.

post8 said

I have not changed any default settings.

I suggest you check those settings and revert them to default if they are not so.