Why does my foreign registered mail contain warnings in EasyPost Connect?

With Connect, there are warnings because our system checks whether the address is correct. In Belgium, a postal code consists of 4 digits, and for foreign countries, it usually consists of multiple digits or a combination with letters (e.g. the Netherlands). Our system then gives a warning like "attention! Is this address correct?" The warning is a reminder to check, but the mail will still be sent.