title: Item Type HTTP Agent not parsing Json Response
body: <p>I have a C# application that return a Json status when I call "<a href="http://host:port/app-status" rel="nofollow noreferrer">http://host:port/app-status</a>". </p>
  
  <p>The response looks like:</p>
  
  <pre><code>{
    "prtg": 
    {
      "result": [
        {
          "channel": "DDS - ZDM - Konsistenzprüfung",
          "value": "3",
          "valuelookup": "prtg.RCLookup.DDS_ZDM_Check.BitField"
        },
        {
          "channel": "ZDM DB Verbindungsversuche",
          "value": "0",
          "valuelookup": "prtg.RCLookup.Default.DB.Connect.Retry"
        }
      ]
    }
  }
  </code></pre>
  
  <p>Then i have on zabbix server an item which type is http agent. 
  The request works fine. But I get this error:</p>
  
  <blockquote>
    <p>Preprocessing failed for: HTTP/1.1 200 Ok..Content-Length: 361..Content-Type: application/json..Server: Grapevine/4.1.1.0 M...<br>
    1. Failed: cannot extract value from json by path ".prtg.result[0].value": cannot parse as a valid JSON object: invalid object format, expected opening character '{' or '[' at: 'HTTP/1.1 200 Ok<br>
    Content-Length: 361<br>
    Content-Type: application/json<br>
    Server: Grapevine/4.1.1.0 Microsoft-HTTPAPI/2.0<br>
    Date: Fri, 12 Apr 2019 14:19:12</p>
  </blockquote>
  
  <p>In the preprocessing tab I have set a processing step with JsonPath.
  The JsonPath is: .prtg.result[0].value</p>
  
  <p>What is wrong?
  Can help me everybody?</p>