Manual:$wgSMTP/Outlook Exchange Server
From mediawiki.org
This page provides an example for setting the $wgSMTP configuration parameter if you would like to use an email account created with your Outlook Exchange Server for sending emails by your wiki.
- STARTTLS
$wgSMTP = [ 'host' => 'outlook.corporatedomain.com', // hostname of the email server 'IDHost' => 'corporationname.com', 'port' => 587, 'auth' => false, 'username' => 'name@corporationname.com', // user of the email account 'password' => '****************' // pass of the email account ];