To solve this problem, there are two solutions:

Put your TV Box on standby: press the key. Just press it again, and you'll be able to watch TV whenever you like.

Modify your TV Box settings:

• Press
• Then select
  French: Paramètres > Système > Image > Sélection HDMI automatique >  Non.
  Dutch: Instellingen > Systeem > Beeld > Automatische HDMI-selectie > Neen.
• Then press to confirm your choice.
• In this case, you'll need to press the and keys to switch on your decoder and TV set when you want to watch TV.