HeroCard Button not posting on click about botframework-emulator HOT 3 CLOSED

{
  "type": "message",
  "attachments": [
    {
      "contentType": "application/vnd.microsoft.card.hero",
      "content": {
        "buttons": [
          {
            "type": "postBack",
            "value": "post back",
            "title": "post back"
          }
        ]
      }
    }
  ],
  "from": {
    "id": "89fk09e0fijjckmal",
    "name": "Bot"
  },
  "recipient": {
    "id": "12345",
    "name": "User 1"
  },
  "replyToId": "ek6n8li8ag3h347dgc"
}

bot.dialog('/', (session) => {
    const card = new builder.HeroCard(session)
        .buttons([
            builder.CardAction.postBack(session, 'post back', 'post back')
        ]);
    const msg = new builder.Message(session).addAttachment(card);
    builder.Prompts.choice(session, msg, "post back");
});