Common WhatsApp API Error Codes and How to Fix Them (2026)

Re-engagement and window errors

These appear when you try to send a free-form message outside the 24-hour customer service window.

• 131047 — re-engagement required: send an approved template instead
• Fix: route anything outside the window through a template message

Recipient and delivery errors

Usually a data-quality problem in your contact list.

• 131026 — message undeliverable: number not on WhatsApp, or blocked
• Fix: validate numbers with country code and remove repeat failures

Template errors

Template issues are the most common cause of a whole campaign failing at once.

• 132000 — parameter count mismatch between template and payload
• 132001 — template does not exist in that language or was deleted
• 133010 — number not registered: complete registration first

Rate limiting and pacing

Throughput and messaging tier limits produce transient errors. Retry with backoff rather than hammering the endpoint, and ramp volume gradually as your tier rises.

Seeing errors clearly in Tizyy

Tizyy surfaces the failure reason per contact in every campaign report, so you can fix the list or template instead of guessing at raw API responses.