参考:phpmailer_init中的代码，可以配置使用SMTP发送电邮

官方的案例代码是:

add_action( 'phpmailer_init', 'my_phpmailer_example' );

function my_phpmailer_example( $phpmailer ) {

    $phpmailer->isSMTP();

    $phpmailer->Host = 'smtp.example.com';

    $phpmailer->SMTPAuth = true; // Force it to use Username and Password to authenticate

    $phpmailer->Port = 25;

    $phpmailer->Username = 'yourusername';

    $phpmailer->Password = 'yourpassword';

    // Additional settings…

    //$phpmailer->SMTPSecure = "tls"; // Choose SSL or TLS, if necessary for your server

    //$phpmailer->From = "you@yourdomail.com";

    //$phpmailer->FromName = "Your Name";

}