Integration failing between Dasher and Homeassistant

[overkill32]

Hello, I am looking for another set of eyes on my configuration. Running Hass v0.60.0 and Dasher v1.4.1.

I am getting button presses just fine via Dasher, but HA doesn’t seem to like the JSON being passed through. Error message as follows:

2017-12-29 19:08:40 ERROR (MainThread) [homeassistant.core] Invalid service data for light.toggle: expected a dictionary. Got '{"entity_id": "light.fireplace_lamp"}'

My Dasher config.json file is pretty much right from the example:

{"buttons":[
  {
    "name": "Debug Dash Button",
    "address": "18:74:2e:e4:c2:c2",
    "protocol": "udp",
    "url": "http://hassbian.local:8123/api/services/light/toggle",
    "method": "POST",
    "body": "{\"entity_id\": \"light.fireplace_lamp\"}",
    "headers": {"x-ha-access": "xxxxxx"},
    "json": true,
    "interface": "wlan0"
  }
]}