Hi you need to lower the security settings in Outlook in order to allow this.
This is from a Microsoft Support article:
When you apply the Microsoft Outlook E-mail Security Update, the Outlook E-mail Security Update provides additional levels of protection against malicious e-mail messages. The Outlook E-mail Security Update changes the way that attachments are handled by Outlook and the way that Outlook can be controlled programmatically.
Note: The Outlook E-mail Security Update is included with Microsoft Outlook 2002, Microsoft Office Outlook 2003, and Microsoft Office Outlook 2007.
To work around this problem, you can customize the behavior of the Outlook E-mail Security Update. You can customize the behavior only if you are running Outlook in a Microsoft Exchange Server environment, and your e-mail messages are delivered to a server-based mailbox.
Note If your mail is delivered to a Personal Folders (.pst) file, you cannot configure the settings for the update.”
On the other hand, are you using an Oracle Database?
If so, you could send mails from the database, with the help of the utl_smtp package, so you don’t need to use outlook at all for your automated e-mail messages.