Step 1: Open Outlook 2007 Step 2: Click the Tools menu, and select Account Settings. Step 3: Click on the Email tab and click on the New… button. Step 4: Select Microsoft Exchange, POP3, IMAP or HTTP and click Next. Step 5: Check the Manually configure server settings or additional server types and click Next. [...]
The most common reason for this error is an incorrectly configured mail client. In order to solve this issue you should reconfigure your email client to successfully authenticate to the SMTP server.

