I can't seem to get my php script to send email.

<?php 
echo "Does this page work?";
mail('my email address', 'test subject', 'test message');
?>

First, I have set the mail function settings in the php.ini file as follows:

I checked my email account settings on outlook. It does not require authentication, its port is 25, and its type of encrypted connection is 'Auto'. Given this I configured my php.ini file accordingly:

SMTP = ssl://smtp1.iis.com
smtp_port = 25

Then I set:

sendmail_from: my email address

The echo statement prints out in the browser, so I know the php file is recognized and processed. But the browser also shows the following error:

Warning: mail() [function.mail]: "sendmail_from" not set in php.ini or custom "From:" header missing in C:\xampp\htdocs\mailtest.php on line 3

I have clearly set the sendmail_from so I don't know what else to do. I have also tried removing the 'ssl://' part from the SMTP setting in the php.ini file, and configuring the php5.ini file. Which of these .ini files should I be configuring anyways?