Firebase，推送通知，无声音（Android）

Question

这是我要发送的有效载荷：

{
  "to" : "cRo7...",
  "notification" : {
    "sound" : "default",
    "title" : "title1",
    "notification" : null,
    "data" : "{\"type\":\"onDemand\"}",
    "icon" : "assets/imgs/back.png",
    "body" : "body3"
  },
  "data" : {
    "sound" : "default",
    "title" : "title1",",
    "notification" : null,
    "data" : "{\"type\":\"onDemand\"}",
    "icon" : "assets/imgs/back.png",
    "body" : "body3"
  }
}

但是我没有任何声音。我也已经通过控制台进行了尝试，并在高级设置中打开了声音，但是仍然没有任何声音。