function makeRequest() as Void {
    System.println("makeRequest");
    var url = "https://url/.....";

    var graphqlQuery = "query getData {getDeviceData(vin: \"VID_12345\") {response {unitid}}}";

    var headers = {
        "Content-Type" => Communications.REQUEST_CONTENT_TYPE_JSON,
        "Authorization" => "Bearer _accessToken"
    };

    var options = {
        :method => Communications.HTTP_REQUEST_METHOD_POST,
        :headers => headers,
        :responseType => Communications.HTTP_RESPONSE_CONTENT_TYPE_JSON
    };

    var body = {
        "query" => graphqlQuery
    };

    Communications.makeWebRequest(url, body, options, method(:onReceive));
}

function onReceive(responseCode as Number, data as Dictionary<String, Object?> or String or Null) as Void {
    System.println("onReceive");
    System.println("Response code: " + responseCode.toString());
    WatchUi.requestUpdate();
}

function makeRequest() as Void { System.println("makeRequest"); var url = "https://url/....."; var graphqlQuery = "query getData {getDeviceData(vin: \"VID_12345\") {response {unitid}}}"; var headers = { "Content-Type" => Communications.REQUEST_CONTENT_TYPE_JSON, "Authorization" => "Bearer _accessToken" }; var options = { :method => Communications.HTTP_REQUEST_METHOD_POST, :headers => headers, :responseType => Communications.HTTP_RESPONSE_CONTENT_TYPE_JSON }; var body = { "query" => graphqlQuery }; Communications.makeWebRequest(url, body, options, method(:onReceive)); } function onReceive(responseCode as Number, data as Dictionary<String, Object?> or String or Null) as Void { System.println("onReceive"); System.println("Response code: " + responseCode.toString()); WatchUi.requestUpdate(); } this is how am using but it's giving me response code -400, any mistakes ?