Hello World

修改 ./wp-includes/functions.php

新增
add_action( 'phpmailer_init', 'send_smtp_email' );
function send_smtp_email( $phpmailer ) {
        $phpmailer->isSMTP();
        $phpmailer->Host       = SMTP_HOST;
        $phpmailer->SMTPAuth   = SMTP_AUTH;
        $phpmailer->Port       = SMTP_PORT;
        $phpmailer->Username   = SMTP_USER;
        $phpmailer->Password   = SMTP_PASS;
        $phpmailer->SMTPSecure = SMTP_SECURE;
        $phpmailer->From       = SMTP_FROM;
        $phpmailer->FromName   = SMTP_NAME;
}

修改 ./wp-config.php

新增
define( 'SMTP_USER',   'user@example.com' );    // Username to use for SMTP authentication
define( 'SMTP_PASS',   'smtp password' );       // Password to use for SMTP authentication
define( 'SMTP_HOST',   'smtp.example.com' );    // The hostname of the mail server
define( 'SMTP_FROM',   'website@example.com' ); // SMTP From email address
define( 'SMTP_NAME',   'e.g Website Name' );    // SMTP From name
define( 'SMTP_PORT',   '25' );                  // SMTP port number - likely to be 25, 465 or 587
define( 'SMTP_SECURE', 'tls' );                 // Encryption system to use - ssl or tls
define( 'SMTP_AUTH',    true );                 // Use SMTP authentication (true|false)
define( 'SMTP_DEBUG',   0 );                    // for debugging purposes only set to 1 or 2

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參考連結
https://gist.github.com/butlerblog/7e4dbafcbc61b15505ee8ca90510f1e7