Hi, I have an Exchange 365 account configured in Apple Mail, along with another 4 IMAP and 2 POP3 accounts. This morning I lost connection with the Exchange server (a user authentication issue) for a few hours. However, I wrote a dozen emails and was able to send them from my main account (the Exchange one)- I heard the "sent sound" everytime. A couple of hours later the authentication issue was solved. To my surprise, I noted that none of the emails had reached their destinations. And I could not find any of them in my Sent mailbox. They were not in the Drafts or Outbox either. Later in the afternoon I managed to replicate the problem. The only explanation I was able to figure out was that messages went somewhere through the servers of one of the IMAP accounts - even though the configuration of the Exchange account says "use only this server". Bottom line, I don't know where are these "sent" messages. They don't appear to be on My Mac, they are not on the Exchange server, and certainly they have not reached their destinations. Any ideas are very welcome! I am not worried about the lost messages, but on being sure it will not happen again without me knowing. Thanks!