Common WhatsApp API Errors and How to Fix Them

The WhatsApp Business API returns error codes that read like they were written for someone who already knows the answer. “Re-engagement message” and “Parameter format does not match format in template” do not tell a marketing manager what to actually do.

Here are the errors Indian businesses hit most often, what each one really means, and the fix.

131047 — Re-engagement message

What it means: You tried to send a free-form message to someone whose 24-hour customer service window has closed.

Why it happens: WhatsApp allows free-form replies only within 24 hours of the customer's last message. After that, only approved templates are permitted. An agent typing a reply the next morning to yesterday evening's enquiry will hit this every time.

The fix: Send an approved utility template instead. Keep two or three general-purpose re-engagement templates approved and ready — for example an order status update or an appointment reminder — so agents are never stuck. A good inbox should show the remaining window time on each conversation so agents can see it closing.

132000 — Number of parameters does not match

What it means: Your template has, say, three variables but you sent two values, or the wrong ones.

The fix: Match the count exactly, in order. This error spikes right after somebody edits a template — adding a variable in the middle silently shifts every downstream position. Re-check any automation that uses a template you have edited.

132001 — Template does not exist

What it means: The template name or the language code does not match what is approved.

The fix: Template names are case-sensitive and language-specific. A template approved as order_update in en will fail if you call it with en_US. This trips up a lot of Indian accounts because both en and en_US exist and look interchangeable.

131026 — Message undeliverable

What it means: The recipient cannot receive the message.

Common causes: the number has no WhatsApp account, the number is formatted wrong, the user has an old app version that cannot render your message type, or the recipient has never accepted WhatsApp's terms.

The fix: Store every number in full international format without a plus sign, spaces or dashes — 919876543210, not +91 98765 43210. Bad formatting is the cause far more often than a genuinely absent account. Clean your database once and the error mostly disappears.

131031 — Account locked or restricted

What it means: Meta has restricted your WhatsApp Business Account, usually for policy violations or a quality collapse.

The fix: This is not a technical problem. Check the Business Manager for the specific violation, stop the sending behaviour that caused it, and appeal if you believe it is wrong. Prevention is the real answer — see our guide to quality rating and messaging limits.

Template rejected: the four real reasons

Template rejection is not an error code but it is the most common blocker for new accounts. In practice, rejections come down to:

1. Wrong category. A promotional offer submitted as Utility gets rejected or silently re-categorised. Marketing content must go in Marketing.
2. Variables at the very start or end of the body, or two variables adjacent to each other. Always wrap variables in fixed text.
3. Placeholder examples that look like spam. Sample values such as “XXX” or “Best offer!!!” get flagged. Provide realistic sample values.
4. Content that reads as unsolicited. No guaranteed-return claims, no aggressive discount language, nothing that reads like a bulk SMS from 2011.

Our step-by-step walkthrough of template approval covers the submission process in detail.

Messages send but never arrive

If the API returns success and the customer still sees nothing, work through this in order:

• Check the status callback, not the send response. A 200 on send means accepted, not delivered. Delivery status arrives asynchronously on your webhook.
• Verify your webhook is actually reachable. An unreachable webhook means you never learn about failures, which makes everything look like silence.
• Check whether the user blocked you. Sent but never delivered, repeatedly, to one number, usually means a block.
• Check the 24-hour window and template category. Marketing templates can be throttled for users who have engaged poorly with marketing content.

Webhook problems that look like message problems

A surprising share of “WhatsApp is broken” tickets are webhook problems on the business side:

• The endpoint must respond with HTTP 200 quickly. Meta retries and eventually backs off if you are slow.
• Duplicate deliveries are normal. Handle them idempotently using the message ID, or customers will get replies twice.
• Signature verification failures usually mean the app secret is missing or the raw request body was modified before verification.

The prevention checklist

1. Store all numbers in clean international format at the point of capture.
2. Keep two or three general utility templates approved for re-engagement.
3. Show the remaining 24-hour window to agents in the inbox.
4. Log every send with its message ID and its final delivery status.
5. Alert on error-rate spikes rather than discovering them from a customer complaint.

ZupiChat handles most of this layer for you: number normalisation on import, the window timer on every conversation, automatic template fallback when the window has closed, and a delivery log that shows exactly which message failed and why in plain language rather than a bare error code. You can try it free for 14 days with your existing API number.

Frequently Asked Questions

What does WhatsApp error 131047 mean?

It means the 24-hour customer service window has closed, so free-form messages are no longer allowed to that contact. The fix is to send an approved utility template instead. Keeping two or three general-purpose re-engagement templates approved means your agents are never blocked by this.

Why do my WhatsApp templates keep getting rejected?

The four common reasons are submitting promotional content under the Utility category, placing variables at the very start or end of the body or next to each other, using unrealistic sample values such as XXX, and copy that reads like unsolicited bulk advertising. Fix the category first, it accounts for most rejections.

What is the correct phone number format for the WhatsApp API?

Full international format with no plus sign, spaces or dashes, for example 919876543210 for an Indian number. Incorrect formatting causes far more undeliverable errors than genuinely missing WhatsApp accounts, so normalise numbers at the point of capture.

The API returns success but the customer never receives the message. Why?

A success response only means the message was accepted, not delivered. Delivery status arrives later on your webhook, so first confirm the webhook is reachable and returning HTTP 200 quickly. Repeated sent-but-never-delivered results for one number usually mean that user has blocked you.

Can I use the same template name in different languages?

Yes, but the language code must match exactly what was approved. A template approved under en will fail if you call it with en_US. Template names are also case-sensitive, which is a frequent cause of the template-does-not-exist error.