When you say Sky channels, do you mean all content from the Sky Q box, including the apps? If it's everything on the box, ensure you're on the correct source for the Sky Q HDMI port on your TV.
Also, you're not muted/volume down, it's easy to do. Worth pulling the HDMI cable out from the TV and the Q bix, and re-insert.
Good luck.
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Samsung UE49MU7070XX - Samsung MS550 Soundbar+ with 9000S Rears
Sky Q 2Tb + 3 Minis - BT Full Fibre 900
