Sending, receiving, and organizing email in Outlook.com
Hi, I'm John! I will help you with this.
Could you share a bit more background, for example, was your account recently hacked/compromised or inactive for a long period?
In the meantime, please check your "Deleted Items" and "Archive" folders, sometimes older messages are automatically moved there. You can also try searching for a specific old email to see if it still appears.
If the issue persists, please provide more details by answering my questions.