Hi Electra,
Welcome to the Humax forum.
You mention Samsung Smart TV, this is nothing to do with your Humax Freesat box. I can’t access your photo so can’t see your screenshot.
Can you still get UKTV App via your Humax Freesat box? If yes, then I can only assume that the TV’s own UKTV app is no longer supported or needs updating. if this TV a new model or at least 5 years old+? Might be worth contacting Samsung for advice. Please let forum know how you get on. John