Hey there, victor.vanhalen!
Sounds like you may be experiencing a form of HD content protection. These issues can usually be resolved by altering the HDMI optionswithin the SlingPlayer for Web!
The Slingbox Forum Moderation Team
I suddenly experienced this 2 sec flickering over the past month.
Tyler is correct, as I've verified the cause to be HDMI and Component (Red, green, blue) were connected to my Cable box ( Motorola DCH3200):
(HDMI goes to TV and components go from Motorola to Slingbox )
1. I unplugged the HDMI from the motorola - no more flickering!
2. Plugged the HDMI cable back in, but turned on the TV - no more flickering!
More info here:
Considered this answered for me!