问发送创建的模板时出现whatsapp api错误

EN

{ "messaging_product": "whatsapp",
 "to": "91********5", 
 "type": "template", 
 "template": {
      "name": "demo_template",
      "language": {
           "code": "en_US" 
           }
            }
             }

{
    "error": {
        "message": "(#132012) Parameter format does not match format in the created template",
        "type": "OAuthException",
        "code": 132012,
        "error_data": {
            "messaging_product": "whatsapp",
            "details": "header: Format mismatch, expected IMAGE, received UNKNOWN"
        },
        "error_subcode": 2494073,
        "fbtrace_id": "ARtWScjGa0rADjfHvbOH4bS"
    }
}