To troubleshoot email sent as an attachment, try the following steps:

1. Check the header of the email to make sure it is set to be sent in HTML format.
2. Verify your settings in Outlook. Set the new email format in More Settings in the Advanced tab.
3. Check HTML Content Encoding, specifically Auto Detects to make sure it is selected.
4. Verify the body of the email is set to HTML rich format.

If your settings are all in the correct format, contact your IT administrator for further assistance.