An inbound message has two distinct stages: received and delivered or undelivered.
Plivo receives an inbound message from a carrier. The user is charged for the inbound message. If the message_url or message_method is not configured in the user's application to the number that receives the message, the message remains marked as "received."
Once Plivo receives a message, it sends a callback with message attributes to the message_url. Based on the response Plivo gets, the message gets recategorized as either delivered or undelivered.
- Delivered: The message_url is valid and active. After sending a callback to the message_url, the state of the message is set to "delivered."
- Undelivered: The message_url is invalid, inactive, or not responding. Plivo will retry callbacks for the next 24 hours. If all callbacks fail, the status of the message will be set to "undelivered."