Sports channels disappearing.

[readyrangers]

Can anybody help me with this, the list is there in bouquets but nothing on channel when you select it. The EPG is all there shows what's on but just a black screen. Every other channel works just no sports channels. Sometimes if you restart the box they come back on again, if you turn off the box at night it is gone in the morning.
Thank you

 

[readyrangers]

I forgot to add it is running vix image. When it does not work it shows the vix emblem up on the top right of the screen, if the emblem is not there it works.