Cannot open interactive dialog

Troubleshooting
8

Anyone can help me with this? I can’t open a dialog.
this is my JSON but i get a 400 error code in my response. I send this JSON to the mattermost api

   `{
      "trigger_id": "a2k0eGhveDN3M2dtN2I0Y3c3b3BobXBoZW86bXlubmk3eGg4M2Y3eDhoMThucjE0c3dvb3I6MTU1NTk1MTg3NjAxNjpNRVFDSUU4VDFqYmNSVGswdDZRQVVFU3haZk5URTg3MUhMT1ozK003aWdsQ01nckhBaUFac290SncwMmFSSkRWNEQyTFN0eXpGY0QySFREeVI2SVg3clY3ejVlMjFnPT0=",
      "url": "https://myapi.com/api/values/service",
      "dialog": {
        "callback_id": "123",
        "title": "Form Test",
        "icon_url": "http://www.mattermost.org/wp-content/uploads/2016/04/icon.png",
        "elements": [
          {
            "display_name": "Display Name",
            "name": "Name",
            "type": "text",
            "subtype": "",
            "default": "default text",
            "placeholder": "Placeholder",
            "help_text": "This is a test regular input",
            "optional": false,
            "min_length": 0,
            "max_length": 0,
            "data_source": "",
            "options": null
          },
          {
            "display_name": "Email",
            "name": "youremail@email.com",
            "type": "text",
            "subtype": "",
            "default": "default text",
            "placeholder": "placeholder@bladekick.com",
            "help_text": "This is a test regular input",
            "optional": false,
            "min_length": 0,
            "max_length": 0,
            "data_source": "",
            "options": null
          },
          {
            "display_name": "Number",
            "name": "Number",
            "type": "text",
            "subtype": "number",
            "default": "",
            "placeholder": "",
            "help_text": "",
            "optional": false,
            "min_length": 0,
            "max_length": 0,
            "data_source": "",
            "options": null
          }
        ],
        "submit_label": "Enviar",
        "notify_on_cancel": false,
        "state": "Default state"
      }
    }`