If Outlook gives the error 'unable to send test message', you may need to update your POP client with patches and bug fixes from the Microsoft Office website. Here's how:
Once your computer has restarted, please try sending and receiving mail via Outlook again.
The Gmail POP Troubleshooter tool helps you with the setup of Outlook, Outlook Express, and Thunderbird 1.5 for Gmail POP access.
By checking client settings, server ports, and your connection to the Gmail service, the tool is able to pinpoint any errors and provide instructions on fixing them. The Troubleshooting tool also generates a report detailing your settings and test results -- if you have trouble, you'll have the option of sending your report to Google for further troubleshooting assistance.
Requirements: works with Outlook 2000, 2002, 2003, and 2007, Outlook Express 6, and Thunderbird 1.5. Currently only available for Windows.
Download the Gmail POP Troubleshooter.