When using Microsoft Outlook, deleting messages on another mail server put them in the trash bin. Now, using Outlook with a Mirapoint Message Server, the messages just get a line marked through them and don't go away.
Your previous mail server probably used the POP protocol for mail retrieval. POP downloads the entire message to your computer, meaning you can see it only from that computer. When you deleted the message, the mail client (Outlook) physically moved the message from one section of your hard disk to another.
The Mirapoint appliance is probably using the IMAP protocol with your email client. All IMAP clients typically download only message headers, keeping your mail on the server where it can be managed regardless of from where you access your mail. To prevent accidental deletion of messages, IMAP clients only mark messages for deletion when you initially select them for removal.
To make the marked-through messages disappear, you must select to purge the deleted messages in your email client.
IMAP clients exhibit similar behavior when you move a message from one folder to another. After the message is moved, the message in the original folder is still present, but marked-through for deletion. These also disappear when you purge deleted messages.