Invalid JSON?

I am receiving this error

{"error":{"code":"RealTime_PushRowsInvalidJson","pbi.error":{"code":"RealTime_PushRowsInvalidJson","parameters":{},"details":[]}}}500

I am sending this post:

var options = {
url: 'myURL',
method: 'POST',
form: {
"Team" :"DAHBOARD",
"Countcasenumber" :"111",
"OpenDate" :"2017-03-29T09:42:56.875Z",
"Status" :"LIVE"
}

And calling it with:

request = require("request");
request.post(options, function (error, response, body) {
if (!error && response.statusCode == 200) {
// Print out the response body
console.log("POWERBI STUFF!!!!" , body + response.statusCode)
        }
    })
}

What is wrong with my Json? it seems to pass in the Json validation.

I am using node.js  with the "request" module.