Why are some of my addresses suppressed for being invalid?

Uploaded addresses are passed through USPS verification and additionally filtered through the Address Strictness level set for the campaign. Addresses can be marked as invalid for a variety of reasons:

• The address has been flagged as vacant or inactive by the USPS
• The address has an invalid primary number.
• The address has missing or invalid secondary information.
• The city/state/zip code combination is invalid.
• The address belongs to a commercial mail receiving agency.

A CSV record of addresses marked invalid is made available after upload.