>>Here is what I see (attached). I think one of the problems is that it's showing wrong content type - it should be JSON. Do you know what should I change?
>
>What do you mean by 'wrong content type'? JSON is there - Fiddler is showing a representation of JSON. Does 'raw' view show the json object ?

Here is what raw view shows:

POST https://dev.citypass.com/integrationapi//Attraction/Tickets/Validate HTTP/1.1
Accept: application/json
Authorization: Basic something here
Cache-Control: max-age=0
Content-Type: application/json; charset=utf-8
Host: dev.citypass.com
Content-Length: 117
Expect: 100-continue
Connection: Keep-Alive

{"TicketBarcode":"BarcodeHere","TicketUsageDate":"2016-10-28T15:09:06.7021957-06:00","UserID":"userNameHere"}

and this is what I am supposed to send:

POST /integrationapi//Attraction/Tickets/Validate HTTP/1.1
Host: dev.citypass.com
Content-Type: application/json
Authorization: Basic different info here (not the one I send)
Cache-Control: no-cache
Postman-Token: 5fabe5b7-5d25-ac19-e81e-0f41a702f793
 
{
  "TicketUsageRequests": [
    {
      "TicketBarcode": "01120800369235",
      "TicketUsageDate": "2016-10-28T15:09:06.7021957-06:00",
      "UserID": "patrick" // User is also different, don't know if it matters
}
  ]
}

Also, in my request I do not see the name of the object - how should I send it as well?