I recently purchased a WD TV Play and have tried to connect to my Slingbox PRO-HD without success. I am persistently getting an error 22 which states that the firmware on my slingbox has not been updated (or, I believe it can mean that the Slingbox itself is not compatible - but in this case it should be because I have a Slingbox PRO-HD). After updating my slingbox firmware, I am still getting the same error. I reset the WD TV Play by pressing the button on the bottom of the device and still ran into the same problem. The Slingbox is still currently working via the mobile app and various computers (both through the app and watch on slingbox.com). I see that others have had similar problems with the WD TV Live but have not seen any resolutions posted. Any help with the problem would be greatly appreciated.
You could try WD technical support or Sling box technical support.