WhatsApp API Errors and Limits Explained in Simple Words

Every answer from the E-Public Touch API tells you clearly what happened. A green answer means success. A red answer has a short error code and a message in plain English. This page explains all the common ones.

How an answer looks

Success:

{
  "status": 200,
  "result": "success",
  "message": "Message sent to WhatsApp.",
  "data": { "messageId": "wamid.HBgM...", "recipient": "919876543210", "status": "accepted", "request_id": 1234 }
}

Error:

{
  "status": 422,
  "result": "failed",
  "error": "WINDOW_CLOSED",
  "message": "More than 24 hours since this customer's last message — only an approved template can be sent now. Use type=template. (Add &force=1 only if you are sure the chat is open.)",
  "data": { "last_customer_message_at": "2026-10-01T18:15:00+05:30" }
}

Your software only needs to check result. If it is failed, show or save the message.

The line under the Send now button says Not sent. See below why and what to do. To see the full answer with the error code (like WINDOW_CLOSED), open Technical details (for your developer) at the bottom of the answer.

Message not received? Start with the checklist

In the tester's left menu, under Help, click Errors. The page starts with a short checklist, Message not received? Go through it one by one: most problems are found in the first few points. Every error code and what to do comes below the checklist.

The most common errors

Several messages in one request

When you send several messages at once (Part 11), a mistake in any of them stops the whole request before anything is sent, and the message starts with the number, like "Message 3: document_url is missing…" (data.item is 3). If WhatsApp refuses one message after sending has started, the answer is "result": "partial" and data.items shows each message as success, failed, duplicate or not_sent.

When WhatsApp says no: common reasons

Sometimes we send the message but WhatsApp refuses it, or it fails later. The hint tells you which one it is:

• Message undeliverable: the number may not be on WhatsApp, or the customer has not accepted WhatsApp's latest terms.
• WhatsApp could not download the file: your file link needs a login or is not a direct file link (see Part 4).
• Template values do not match: wrong number of values or wrong language.
• Template paused: too many people blocked or reported it. Improve the template or use another one.
• Form not found: the form ID is wrong, or the form is not published yet. Check it on the My forms page (Part 6).
• Marketing limit: WhatsApp limits how many marketing messages one person gets. Try later, or use a utility template for real updates.
• Payment problem: the payment method for your WhatsApp account needs attention. Message our team.

Limits you should know

WhatsApp also has its own daily limit on how many new people your number can message with templates. It grows as your number builds a good record.

Duplicate protection: why a message went only once

• If the same link is opened twice within 2 minutes, we send it only once. The second answer says "Already sent … — not sent again". This stops double clicks and browsers that open a link twice.
• Add your own ref (like an order number) to be fully safe: the same ref is never sent twice within 24 hours, even with POST.
• A failed send never blocks a retry.

Indian mobile numbers

You can write numbers in any of these ways. We clean them up for you:

• 9876543210 → we add 91 → 919876543210
• 09876543210 → we remove the 0 and add 91
• +91 98765-43210 → spaces, + and - are removed

For other countries, always write the country code.

Still stuck? Quick checklist

Sending from your own software and it still does not work? Check these too:

1. Is the key copied fully, with no space at the start or end?
2. Is the number correct and on WhatsApp?
3. Has the customer written to you in the last 24 hours? If not, use a template.
4. Is the template Approved, with all values filled?
5. Does your file link open the file directly in a private browser window?
6. Check Recent API calls in your panel. The message column shows the reason.

If it still does not work, send us a screenshot of the red answer on WhatsApp. Please hide your key before you share it.

What next?

Using another WhatsApp API today? Part 10 shows how to move your old links to E-Public Touch in a few minutes.

Next: Part 10 — Moving from another provider