First Template Message Not Delivered Unless User Sends a Message First

Problem: I’m using the Meta WhatsApp Business API to send template messages. When I try to send the first message using Postman, I get a 200 OK response, but the message is not delivered to the recipient's phone. However, if the user sends me a message first, the API works as expected, and the message is delivered.

Here is the JSON request I'm using:

{   "messaging_product": "whatsapp",   "to": "91790******",   "type": "template",   "template": {     "name": "hello_world",     "language": {       "code": "en_US"     }   } } 

The response I receive is:

{   "messaging_product": "whatsapp",   "contacts": [     {       "input": "91790******",       "wa_id": "91790******"     }   ],   "messages": [     {       "id": "wamid.HBgMOTE3OTA0NjMwMzM3F***dfdffQkI1QzcwNTd**==",       "message_status": "accepted"     }   ] } 

I’ve confirmed that the template (hello_world) is approved and active. The API request returns a 200 OK response, but the message is still not delivered to the recipient unless they initiate the conversation by sending a message first.

Question: Why is the message not being delivered when sending it as the first message? How can I send the first template message without requiring the user to send a message first?

Additional Details: I’m using the Meta WhatsApp Business API. The template is approved, and the recipient's phone number is valid.