How long does a message stay in WhatsApp?
When you send a message, as soon as you get back a message ID, that means the message request has been stored on the database. The WhatsApp Business API Client will keep attempting to send that message until acknowledged by the WhatsApp server. This process has no end timeline. The WhatsApp server will then try to deliver that message to the user's phone. If the user's phone is not online, the message will be stored for 30 days before being discarded by the WhatsApp server.