We need you to be more specific. Unfortunately, your post is not clear enough and we need you to give us as much information as possible. How's the TV connected, using a splitter or with a Pass-Through from the Slingbox?
Let us know how it works
Thanks for your interest, but i solved my problem;
contacting SlingMedia customer service, i discovered that my SlingBoxPro had hardware problems (some components in the circuit board warmed up at too high temperature: this caused malfunctions), then SlingMedia sent me a new one and i returned my damaged SlingBoxPro.
Now i have a new SlingBoxPro, working perfectly!