Particle Cloud Webhook doesn't work correctly when trying to send string as argument

Hi everyone,
I kind of ran out of idea for what I should do to fix this.
This is my data from my code

  String msg = String::format("{ \"wl1\": %0.5f, \"wl2\": %0.5f, \"wl3\": %0.2f, \"temp\": %0.2f, \"b\": %0.2f, \"at\": %s }", 
                              111.00230, 111.44421, 111.33, 30.11, 40.22,"2020-01-23T05:46:16Z");

Event in the Webhook

{
  "name": "Boron-1",
  "data": "{ \"wl1\": 111.00230, \"wl2\": 111.44421, \"wl3\": 111.33, \"temp\": 30.11, \"b\": 40.22, \"at\": 2020-01-23T05:46:16Z }",
  "ttl": 60,
  "published_at": "2020-01-23T06:22:19.218Z",
  "coreid": "XXXXXXXXX"
}

*This is my JSON

{
    "event": "Boron-1",
    "url": "*******",
    "requestType": "GET",
    "noDefaults": true,
    "rejectUnauthorized": false,
    "query": {
        "email": "xxxxxxx",
        "api_key": "xxxxxxx",
        "WL1": "{{{wl1}}}",
        "WL2": "{{{wl2}}}",
        "WL3": "{{{wl3}}}",
        "B": "{{{b}}}",
        "at": "{{{at}}}"
    }
}

This is what I got on the Request

GET /measurements/url_create?instrument_id=20&at=&B=&WL3=&WL2=&WL1=&api_key=xxxxx&email=xxxxx HTTP/1.1
User-Agent: ParticleBot/1.1 (https://docs.particle.io/webhooks)
host: xxxxxxx
Connection: keep-alive

Before I added “at” = “{{{at}}}”, it was working fine. The Request was this.

GET /measurements/url_create?instrument_id=20&B=40.22&WL3=111.33&WL2=111.44421&WL1=111.0023&api_key=XXXX&email=XXXXXX HTTP/1.1
User-Agent: ParticleBot/1.1 (https://docs.particle.io/webhooks)
host: XXXXXX
Connection: keep-alive

Please help I have no idea what I’m doing wrong.

Thanks in advance,
Phisuthisak

You need to wrap your at value in double quotes otherwise the entire JSON will be invalid.

It’s working now. Thanks a lot.