Thanks for contacting us here on the forums!! It appears you may be running into copyright protection issues and unfortunately resetting the cable box does not resolve that since this is something that the cable company places on the cable box. I have included a couple of support articles that will explain this and provide a resolution:
- Slingbox.com - Using an HDMI video source with the Slingbox 500
- Slingbox.com - Why is your HDMI input disabled in Watch on Slingbox.com?
If you have any further questions please feel free to contact us again!!
Hope this helps!!