If the recipient can't find the message in their Inbox folder, the message might have been deleted or moved to another folder ...


If the recipient can't find the message in their Inbox folder, the message might have been deleted or moved to another folder (such as Junk Email) either manually or automatically based on an Inbox rule or Sweep rule the recipient set up. Ask them to search for the message across all folders in their mailbox.

Tip: If the recipient still can't find the message in Outlook, they might be having connection problems. Ask them to try restarting Outlook or use Outlook on the web to check their mail instead.
To troubleshoot Outlook problems, download Support and Recovery Assistant for Office 365.