If you are getting an error that the Slingplayer cannot connect to the Slingbox, there are a few different things you will want to look in to. The first thing you will want to check is that your Slingbox is connected to your home network and is able to maintain that connection. It can also mean that your particular device is not getting an internet connection. The article below will help you to reset your Slingbox connection if it is not connected to the network currently.
Hope this helps!
Sling Media Support