melanogaster on Unable to clear a channel via Arduino

Thanks for the Reply.

I allready tried many changes in the HTTP method.

For example i tried this Code:

String apiKeyUser = XXXXXXXXXXXXXXXXXXXX;

String apiKeyChannel = XXXXXXXXXXXXXXXXXXXX;

String channelID = XXXXXX;

if (client.connect(server,80)) { // "184.106.153.149" or api.thingspeak.com
   String postStr = "api_key=";

   postStr += apiKeyUser;
   client.println("DELETE /channels/"+channelID+"/feeds HTTP/1.1");
   client.println("Host: api.thingspeak.com");
   client.println("Connection: close");
   client.println("X-THINGSPEAKAPIKEY: "+apiKeyChannel);
   client.println("Content-Type: application/x-www-form-urlencoded");
   client.print("Content-Length: ");
   client.println(postStr.length());
   client.println();
   client.print(postStr);
}

I thought it would work, but it did not.

Also i have no idea why there is this part of the Code:

  client.println("Host: api.thingspeak.com");
   client.println("Connection: close");
   client.println("X-THINGSPEAKAPIKEY: "+apiKeyChannel);
   client.println("Content-Type: application/x-www-form-urlencoded");
   client.print("Content-Length: ");
   client.println(postStr.length());
   client.println();

I think it is there for HTTP coding or something like that.

Still, the Code does not work...

Any ideas?