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Troubleshooting
Interpret calc errors, 429 rate limits, HS code lookup fallbacks, and upload failures.
Common calculator errors and how to interpret them
The five error messages you are most likely to see in the calculator, what they mean, and how to fix them.
2 min read · Updated 2026-08
429 rate-limit responses on the API
The /v1 API limits every key to 60 requests per minute. Here is what a 429 looks like, how to back off, and how to design your client to avoid them.
2 min read · Updated 2026-08
HS code not found in the calculator
The calculator rejected your HS code. Here is why, how to check it against the current tariff schedule, and how the semantic lookup fallback works.
2 min read · Updated 2026-08
Upload failures and OCR fallback
Your CBP 7501 or other entry document failed to upload or parsed with low confidence. Here is how the deterministic parser and OCR fallback interact.
2 min read · Updated 2026-08