- When using mail client with mailbox email@example.com subdirectory "sent mail" (or "sent") is not created and already sent mail is put in "outgoing mail" directory.
- When using mail client with other mailboxes, for example firstname.lastname@example.org subdirectory "sent mail" (or "sent") created and already sent mail is normally put in "sent mail" directory.
- Switching IMAP server from Dovecot to Courier (and vice versa) using Plesk UI does not resolve the issue.
Mailbox is corrupted.
Note: Since RFC for IMAP protocol does not specify a naming convention for folders like "Sent", it is possible that different mail clients would create different folders to save messages in there. Folders like "Sent", "Drafts", "Junk" and "Trash" are created automatically when the client logins using Roundcube, or Horde. Mail client software should use these folders if they exist at the account creation time. In case they did not, it is recommended to create a rule to move sent messages to the specific folder.
Make backup of mailbox contents and recreate it in Plesk:
2. Create backup directory and copy all contents of mailbox to backup directory:
# mkdir /root/backup-mailbox/
# cp -rp /var/qmail/mailnames/example.com/johndoe/* /root/backup-mailbox/
3. Login into Plesk and remove mailbox via Plesk UI: Domains > example.com > Email addresses > check mailbox "email@example.com" and click Remove.
4. Using SSH command ensure that mailbox's folder is actually removed:
# rm -f /var/qmail/mailnames/example.com/johndoe
5. Create new mailbox with same name "firstname.lastname@example.org" via Plesk UI: Domains > canalplast.it > Email addresses > click Create mailbox and type "email@example.com".
6. Copy messages from backup directory to directory of mailbox "firstname.lastname@example.org":
# cp -rp /root/backup-mailbox/* /var/qmail/mailnames/example.com/johndoe/
7. Log into webmail with username "email@example.com" and send test email to intialize "send" folder.