Bulk Tracking: Exception: Invalid idSite: '0'

Hi all,
I have a issue regarding the bulk tracking. I tested the example request via curl as it is written in the documentation

curl -i -X POST -d ‘{“requests”:["?idsite=all&url=http://mySite/app&action_name=test&re
c=1","?idsite=3&url=http://mySite/app2&action_name=Test2&rec=1"],“token_auth”=“xxxxx”}’ http://MyPiwikInstance/piwik.php

The data is, of coursed, replaced by placeholders.
From my point of view there are no syntax issues in this command but executing it returns us the result below.
The idsite=3 exists. I was a little bit confused because the error message includes “idSite” in camel case. I tried both versions but the results are still the same. Any ideas why this happens?
Piwik Version: Tried on 2.16.2 => error. Update on 3.0.2 => same error
curl is running on a windows 7 64bit machine.

Thanks for your help in advance!

HTTP/1.1 400 Bad Request
Content-Type: text/plain;charset=UTF-8
Server: Microsoft-IIS/8.5
X-Powered-By: PHP/5.6.22
Access-Control-Allow-Origin: *
Access-Control-Allow-Credentials: true
X-Powered-By: ASP.NET
X-UA-Compatible: IE=edge
Date: Thu, 02 Mar 2017 08:19:38 GMT
Content-Length: 3299
Via: 1.1 xxx
Connection: Keep-Alive

DEBUG: Debug enabled - Input parameters:
DEBUG: array (
DEBUG: ‘’{requests:_?idsite’ => ‘all’,
DEBUG: ‘url’ => ‘xxx’,
DEBUG: ‘action_name’ => ‘Test2’,
DEBUG: ‘rec’ => ‘1],token_auth=removed}’’,
DEBUG: )
DEBUG: Current datetime: 2017-03-02 08:19:38
DEBUG: Executing Piwik\Plugins\CoreHome\Tracker\VisitRequestProcessor::manipulateRequest()…
DEBUG: Executing Piwik\Plugins\Actions\Tracker\ActionsRequestProcessor::manipulateRequest()…
DEBUG: Executing Piwik\Plugins\Goals\Tracker\GoalsRequestProcessor::manipulateRequest()…
DEBUG: Executing Piwik\Plugins\Ecommerce\Tracker\EcommerceRequestProcessor::manipulateRequest()…
DEBUG: Executing Piwik\Plugins\SitesManager\Tracker\SitesManagerRequestProcessor::manipulateRequest()…
DEBUG: Executing Piwik\Plugins\CustomVariables\Tracker\CustomVariablesRequestProcessor::manipulateRequest()…
DEBUG: Executing Piwik\Plugins\Heartbeat\Tracker\PingRequestProcessor::manipulateRequest()…
DEBUG: Executing Piwik\Plugins\CoreHome\Tracker\VisitRequestProcessor::processRequestParams()…
DEBUG: Exception: Invalid idSite: ‘0’

It seems that it was an error with curl. In my C# application the request works fine and that was the main goal. curl was just for testing. Unfortunately not very successful…