Invalid postal code

Error 737 (and related codes 17103/17804/17805/17806) means the postal code submitted doesn't match the format required for the listed country. The listing is blocked.

Common breaks: 5-digit US ZIP submitted for UK listings (UK needs alphanumeric like SW1A 1AA), country mismatch (US ZIP for a Canadian listing), trailing whitespace, or US 9-digit ZIP+4 submitted where only 5 are accepted.

1. Validate every postal code against the country's official format.
2. Strip whitespace and ensure no hidden characters from CSV exports.
3. Use 5-digit ZIPs for US, 6-digit alphanumeric for Canada, the standard pattern for UK.
4. Apply a regex check in your feed pipeline before submission.
5. Resubmit once the postal code is valid.

• Excel auto-stripping leading zeros from northeastern US ZIPs (01234 -> 1234)
• Mixing 9-digit ZIP+4 with 5-digit-only API endpoints