There are two easy ways to verify address data in your contact lists. The first is to use a USPS® address verification tool. These tools can verify both US-based addresses as well as international addresses in batches. The second method is to use an address validation API.Jul 12, 2021
Why can't USPS verify my address?
USPS Doesn't Recognize My Address! Sometimes, an address will not validate because the address is marked as "vacant" by the USPS. Additionally, a new address, an unregistered address, or one located within a postal code primarily serviced by PO boxes, would all fail to validate.