How to view details on E-Mail delivery:
Right-Click on a message in your 'Sent Folder' and select - "Open Delivery Report"
and details on the current message will be displayed.
Note: If you are prompted with a pop-up blocker message - select 'Yes" to allow.
You will continue to get this message each time unless you click on 'Options'
on the browser title bar. The image example below is for Firefox but Internet
Explorer has a similar notification asking if you want to add site - say 'Yes'.