It should be found in the Outbox. That box is normally hidden, but when a message is stopped, fails to be sent or is saved as a draft, it becomes visible, so that message can be accessed. Of course, it's possible your wife selected an option that deleted the message when she got the "unable to send" alert. (I'm not sure off the top of my head what the options are.)
Thanks, but the Outbox is not visible. She did not make any selections. The mail made the normal whoosh sound like it was sent, but then she got the Mail Delivery Subsystem Returned mail message. It shows all the detail , which in this case was that the address had permanent fatal flaws. At that point, there was nothing to select. It was gone and there was no outbox.
If the message actually sent, then it should be in the Sent mailbox, even it it got rejected afterwards. Check the Mail settings and make sure it's set to save sent messages.
If it's an IMAP account, you might check the IMAP sent folder or the webmail site for it if you have it storing sent messages on the server.
And I did test this by sending a message to a fake address. Sent message was in the Sent Mailbox and immediate failure message came in.
Also note that at the bottom of the failed message was the text I sent.
Well, it did not appear in the Sent mailbox. The settings are correct in that Sent messages are saved and go into that mailbox. All the other emails she sent last evening are in the Sent box, but not this one. It is an IMAP and is stored on the server, but I went to AOL and it is not there, either, just the rest of her emails.
As opposed to your experience, the text of her message does not appear at the bottom of the rejection message. It is just an entire page ot techo-babble. We may be talking two different things. This was not an immediate failure message, where the message does not go out. In this case, the whoosh occurred like a normal message going out, then this detailed Unable to Deliver message came into the inbox. This is not the window that pops up on the screen when you try to send an email and there is a problem, such as no address, subject, etc.
I understand the message was sent and that's why I said it should be in the Sent mailbox.
I used ATT email for test. That was my experience. AOL may work differently on content of the returned failed message.
As for why it doesn't appear in the sent mailbox, I can't explain that. It should have been there. I guess it's possible that AOL works a bit differently where you only get a sent message if it successfully reaches a ligetimate address.
If you are storing draft messages on the server, then maybe check the draft mailbox in the IMAP draft folder or website. It could have gotten copied as a draft while you were composing.
If you don't store drafts on the server, once a message is sent, the temporary draft gets deleted. Your message sent, so you will have no local draft saved.
Other than that, there is no way to retrieve it.