Mail that was there and now is not.
FIRST, SEARCH PROPERLY
Search the whole mailbox rather than the current folder. Many clients default to searching only what is open.
Check Trash, Junk, Archive and any folder a filter might have used.
CHECK YOUR FILTERS
A rule created months ago may be moving or discarding mail. cPanel > Email Filters, and the filters in webmail.
CHECK OTHER DEVICES
If any device uses POP3 with "remove from server", it has downloaded and deleted the mail. That device holds the only copy.
CHECK FOR A COMPROMISE
Mail deleted in bulk that nobody deleted, especially alongside forwarding rules you did not create, indicates a compromised mailbox. Change passwords and open a ticket.
RESTORING FROM BACKUP
Where JetBackup covers email on your plan, mail can be restored from a date. Open a ticket with the mailbox and the date, and be aware retention is finite.
PREVENTION
Use IMAP, keep an archive on your own computer, and do not rely on the server as the only copy.
