This is the message I got this morning when I tried to view my slingbox remotely from my work computer. I was using it fine last night, both the TV and slingbox were displaying the content perfectly fine at the same time. Now all of a sudden this. What the heck?
The problem is due to your set-top box's interoperability with the digital and analog outputs. Its possible that your television provider pushed an update to your set-top box enabling High-bandwidth Digital Content Protection (HDCP).