Hi! Your Outlook may not have synchronized the email, or it may have blocked the email if it contains something suspicious, or the sender may not have sent it.
- Check your spam (junk mail) folder.
- Check if the sender's email address is blocked.
- Check with the sender if the email left their outbox. Perhaps the email was not sent or was blocked.
- Ask the sender to resend the email. If the email has any attachments, ask them not to attach any files and send the email.
- See if the email appears in Outlook Web: https://outlook.live.com/