Oops, can’t really see how that can happen as it’s all digital, just a few ideas…
have you rebooted the humax and tv, i.e. physically switched them off and on again.
what resolution do you get when you press the v-format button? and does toggling through help
can you connect and check with scart
have you any other hdmi devices connected and are they blurred, if not can you swap hdmi inputs, if the other devices are also blurred then it’s the tv, also if the tv’s own tuner is blurred then it has to be the tv