Here are some things you can do if you are missing or lost emails in your Outlook account:

1. Check doubtfully placed emails: maybe your email got placed in a different folder than you expected.
2. Check Spam folders: it’s possible that your email got flagged as spam by the system.
3. Configure email filters: you can create email filter to automatically move emails from certain senders to specific folders.
4. Disable new email notifications: certain notifications about emails prevents Outlook from downloading or displaying them.
5. Check if you can retrieve deleted emails: instructions on how to do this can be found on the Outlook help page.