Why do my "sent" messages no longer appear in my Sent file, or anywhere else?
When I reply to an e-mail, or create an e-mail and send it, the message no longer appears in my "Sent" file -- which it always did until just recently.
Opaite Mbohovái (1)
Firefox doesn't do email, it's strictly a web browser.
If you are using Firefox to access your mail, you are using "web-mail". You need to seek support from your service provider or a forum for that service.
If your problem is with Thunderbird, let us know and we can move this thread to the Thunderbird queue. This question currently is in the Firefox queue for answers.