This error indicates the postal code being entered in the field is not the correct format for the country being selected.
You may also look online to determine what format to enter international postal codes (Example: Canadian postal codes follow a specific format. They are 6 characters long, and split by a space. When entering an address with Canada selected as a country, you will need to enter the postal code under the following format: A1A 1A1.)
PLEASE NOTE: If you still receive an error message after attempting an alternative format for the postal code, you must have a US mailing address when registering.