Microsoft Invest - Invalid postal and ZIP codes
Certain real ZIP or postal codes can be invalid within the Microsoft Advertising geography targeting system. This happens when Digital Envoy, a Microsoft Advertising partner that handles geolocation data, can't recognize a ZIP or postal code's existence because no IP address (internet user) has been associated with it.
Postal codes that don't exist in the system often represent obscure or otherwise small geographical zones with minimal internet activity. Additionally, certain ZIP or postal codes that are in close proximity to or overlap with other ZIP or postal codes may be considered invalid. Digital Envoy constantly updates its postal code database, so a ZIP or postal code's invalid status within the Microsoft Advertising geography targeting system is always subject to change.