795338 - Error 421 response from server results in message not being sent but being placed in "Sent" folder

Status: RESOLVED DUPLICATE of bug 780124

(Thunderbird :: Folder and Message Lists, defect)

Description

[jollygreenfat]

Attachment: excerpt of logs detailing successful & failed sends.

(Using 15.0.1) Occasionally when I attempt to send mail via Yahoo's SMTP server (plus.smtp.mail.yahoo.com), the server is unavailable and replies with "421 Resources temporarily unavailable - Please try again later". Thunderbird pops up a dialog detailing this error message, but still ends up placing the message in question in the "Sent" folder instead of retrying/etc. The message is NOT sent, but once the error dialog is cleared there's no way to know this within the software.

I managed to capture logs of both successful & unsuccessful sends (attached). I've also mentioned this issue in the mozillaZine forums here:

http://forums.mozillazine.org/viewtopic.php?f=39&t=2544875

As seen in that forum, this is an issue others are seeing as well.