Message undeliverable: error 131026

Error 131026 means WhatsApp could not deliver the message. Meta lists several possible causes, so the code alone does not establish one diagnosis.

Check with the recipient

Use another communication channel to ask the recipient to:

1. Confirm the phone number is registered with WhatsApp.
2. Check whether they can send a WhatsApp message to your business number.
3. Accept any outstanding WhatsApp Terms of Service or Privacy Policy prompts.
4. Update WhatsApp to the latest available version.

Meta lists an unregistered number, unaccepted terms, and an old client version among the possible causes. Refer to the current WhatsApp error-code reference for the latest guidance.

Keep the error details for support

If the error response includes fbtrace_id, keep that value with the error code and the time of the failed attempt. It can help support investigate the request. Share diagnostic details through the support channel, rather than posting customer numbers or complete error payloads publicly.

Do not assume the code proves that the recipient blocked your business or that the account has been restricted.