add_action( 'phpmailer_init', 'setup_phpmailer_init' );
function setup_phpmailer_init( $phpmailer ) { $phpmailer->Host = 'HOSTNAME'; // for example, smtp.mailtrap.io $phpmailer->Port = 587; // set the appropriate port: 465, 2525, etc. $phpmailer->Username = 'YOURUSERNAME'; // your SMTP username $phpmailer->Password = 'YOURPASSWORD'; // your SMTP password $phpmailer->SMTPAuth = true; $phpmailer->SMTPSecure = 'tls'; // preferable but optional $phpmailer->IsSMTP();