Status details

A status says what happened to a message; a status detail says why. It is a two-level code category.reason returned next to the status:

status_detail field — JSON status and webhook;
status_detail attribute — XML status;
status_detail: line — HTTP status;
status_detail parameter — delivery report.

Rules:

The detail is present only when the reason is known. Otherwise there is no such field, and the response is exactly as before.
The status itself does not change: a message with undelivered.no_viber_user keeps its undelivered status.
A detail belongs to the channel the message is on. If an undelivered Viber message is resent by SMS, the Viber reason no longer applies and the detail disappears.
New codes are added over time, existing ones are never renamed. Treat an unknown code as "no detail" and keep processing the status.

Categories: undelivered — the message did not reach the recipient; rejected — it was refused before delivery because of the sender, the template or the content.

Code	Description
`undelivered.no_viber_user`	The number has no Viber
`undelivered.no_whatsapp_user`	The number cannot receive WhatsApp: no account or an outdated app
`undelivered.blocked_by_user`	The recipient has blocked the sender
`undelivered.opted_out`	The recipient has opted out of marketing messages
`undelivered.marketing_limit`	The messenger limited marketing messages to this recipient
`undelivered.no_suitable_device`	No device of the recipient can receive the message
`undelivered.no_route`	No delivery route to the number
`undelivered.provider_error`	Failure on the side of the delivery channel
`rejected.spam`	Blocked as spam
`rejected.blacklisted_word`	The text contains a forbidden word
`rejected.sender_not_permitted`	The sender is not approved or not allowed to send
`rejected.message_type_blocked`	This message type is not allowed for the sender
`rejected.outside_service_window`	WhatsApp: 24 hours have passed since the recipient last wrote — send a template
`rejected.template_not_found`	Template not found
`rejected.template_unavailable`	The template is paused or disabled
`rejected.template_parameters`	The parameters do not match the template
`rejected.invalid_text`	The text is empty or too long
`rejected.invalid_media`	Invalid attachment: image, video, file or its caption
`rejected.invalid_button`	Invalid button or button link
`rejected.invalid_carousel`	Invalid carousel
`rejected.invalid_parameters`	Other invalid message parameters

Example — JSON status of a Viber message that was not delivered because the number has no Viber:

{
    "msg_id": 123456789,
    "type": "viber",
    "status": "REJECTED",
    "success": false,
    "updated": "2026-10-20T12:34:00+03:00",
    "status_detail": "undelivered.no_viber_user"
}