WhatsApp API Issue - Message Delivery Inconsistency

Question

I am reaching out to report an issue I have been experiencing while using the WhatsApp API for sending messages. The problem involves an inconsistency between the response I am receiving from the API and the actual delivery of the message.

I am using .Net core requests library to send POST requests to the API endpoint: https://graph.facebook.com/v18.0/\<FROM_PHONE_NUMBER_ID>/messages

Payload is as below

{
    "messaging_product": "whatsapp",
    "contacts": [{
            "input": "<PHONE_NUMBER>",
            "wa_id": "<PHONE_NUMBER>"
        }
    ],
    "messages": [{
            "id": "wamid.<Message_ID>"
        }
    ]
}

I am sending two types of messages: template messages and text messages.

However, the text message is not received on my phone. I have tested this with two different phones and the result is the same.

On the other hand, when I send a template message using a similar method, I also receive an HTTP 200 response and the message is successfully received on my phone.

I am unable to understand why this inconsistency is occurring. The API suggests that both requests are being processed successfully, but only the template message is being delivered.

Any insight you can provide into this issue would be greatly appreciated.