When a message fails, it can fall into two categories: Undeliverable or Failed.
What does Undeliverable mean?
A message is marked as Undeliverable when WhatsApp cannot send it to the recipient because:
The phone number is not registered on WhatsApp.
The recipient has not accepted WhatsApp’s Terms of Service and Privacy Policy.
The recipient is using an outdated version of WhatsApp.
The recipient has blocked your number.
What does Failed mean?
The Failed status means that WhatsApp tried to send your message, but a problem prevented its delivery to the recipient.
This can happen for several reasons, for example:
Meta decided not to send the message to protect the ecosystem.
You attempted to send a message outside the 24-hour conversation window without using a pre-approved template.
WhatsApp temporarily blocked delivery due to policy or quality rules.
There was a temporary system or connectivity issue.
When a message shows the status Failed, it means WhatsApp has stopped trying to deliver it.
The message will not reach the recipient unless you send a new one later.
What does Pending mean?
A message is Pending when WhatsApp has tried to send it, but it has not yet been delivered to the recipient. The most common reasons are:
The recipient does not have an Internet connection (no data or Wi-Fi).
The recipient’s phone is turned off.
After 120 days, the message delivery will be canceled and it will no longer be delivered.