HTTP POST does not work


I wrote a web service that is storing values in a database.
I can call the service in a browser via this URL:

Now I try to do the same on my ESP8266 board - looks like this:

String yourdata = "param=Temperature&user=ESP12E_001&value="+ String(temp);
client.println("POST /api/values HTTP/1.1");
client.println("User-Agent: Arduino/1.0");
client.println("Connection: close");
client.println("Content-Type: application/x-www-form-urlencoded;");
client.print("Content-Length: ");

For any reason that I do not understand all I get is this:

HTTP/1.1 404 Not Found
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/json; charset=utf-8
Expires: -1
Server: Microsoft-IIS/10.0
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Sun, 22 Nov 2015 20:19:51 GMT
Connection: close
Content-Length: 130

{"Message":"Es wurde keine HTTP-Ressource gefunden, die mit dem Anforderungs-URI "" übereinstimmt."}

Any hint anyone ?


The server can’t find the path/file you requested.

I can call the service in a browser via this URL:

That is NOT generating a POST request. It is generating a GET request.