Picture format on my sky box has changed unbidden to zoom and is frozen on zoom

[Tac25]

I set the picture format on my sky box to a ratio of 16.9. A couple of weeks ago, although the setting is still 16.9 the actual picture displayed changed to zoom and won't budge from zoom.

How to fix?

[Exiled-in-HH]

Check your TV's setting🤔