Do you know why do people get this message whenever they send something to me?

Can we solve this problem? 

This is the message that anybody will receive if they send something to *** Email address is removed for privacy ***: 

This is an automatically generated Delivery Status Notification.  Delivery to the following recipients failed.         *** Email address is removed for privacy ***     Final-Recipient: rfc822;djepra_maldini@hotmail. Action: failed Status: 5.5.0 Diagnostic-Code: smtp;550 Requested action not taken: mailbox unavailable

Thanks,

Jeremy