TicketsNow is a subsidiary of Ticketmaster or Ticketbastard if you prefer. The 'sold out' status is easy to explain. Basically the actual venue has 'sold out' of tickets having likely supplied a large number of ticket vendors with an allocation at the start of sale. The venue registers these tickets as sold although it is evident that some of these vendors have tickets left. Still only 220 to go at the time of writing!
I'm surprised someone from HBO didn't shoot you in the neck with a dart before you posted this topic.