Manual:$wgSMTP

Details
For using a direct (authenticated) SMTP server connection, you need to fill an array with details about your connection. Set to false (the default value) to use the built-in PHP mail function.

For example:

'IDHost' is a MediaWiki-specific setting used to build the Message-ID email header (see RFC 2822, sec 3.6.4 for more information on a properly formatted Message-ID). If not provided, will default to $wgServer. For the remaining settings, see Mail::factory for a more complete description. (Scroll down to the  parameter.)

This setting requires PEAR's Mail package to be installed (run, and you can run "pear list" to confirm). If you get an error message stating that pear is not installed, then install  and then try again.

Examples

 * Outlook Exchange Server

Error sending mail: Unknown error in PHP's mail function Mediawiki
See possible issues in.

As a possible workaround, put the following into LocalSettings.php, making the necessary substitutions for yourEmailAccount and yourEmailPassword:

Then install the packages required to send the mail.

After this you may get an authentication failure type error. You will need to sign into the gmail account you are using and verify that the person that just signed in is you. You only need to verify this one time. (gmail will send you an email and you just follow the instructions)

Error sending mail: authentication failure SMTP: STARTTLS
PEAR's mail will try to use TLS when connecting to the mail server if the server supports it, even if you don't specify ssl:// in the host. But if the server certificate is not valid (CA not trusted, certificate has expired, etc) it will refuse to work, and instead you'll get the following error:

authentication failure [SMTP: STARTTLS failed (code: 220, response: begin TLS negotiation)]

You must fix the certificate issues for mail to work.