PHP errors

I have PHP error checking turned on, and I get this error from the plugin:

PHP Warning: The URL https://raiserweb.com/wp-update-server-master/?action=get_metadata&slug=woocommerce-email-test&license_key=false&checking_for_updates=1&installed_version=1.8 does not point to a valid plugin metadata file. HTTP response code is 403 (expected: 200) in (path-to-my-site)/wp-content/plugins/woocommerce-email-test/plugin-update-checker/plugin-update-checker.php on line 969

I think they need to update their plugin.