WP Mail SMTP: when using SMTP mailer - disable SSL verify on PHP 5.6+

wpms-smtp-disable-ssl-verify.php

<?php

add_filter('wp_mail_smtp_custom_options', function( $phpmailer ) {
	$phpmailer->SMTPOptions = array(
		'ssl' => array(
			'verify_peer'       => false,
			'verify_peer_name'  => false,
			'allow_self_signed' => true
		)
	);

	return $phpmailer;
} );

It works, thank you. For those wondering where to put this, the cleanest possible way is to use the Code Snippets plugin:

https://wordpress.org/plugins/code-snippets/