Either look on the device for the model or go into settings and look for the system information (and then ask in the correct section) otherwise no-one here will have any clue.
Hi I have two identical humax boxes one downstairs one in the bedroom, both show a message signal scrambled
If you are in the South of England then it is probably due to the current weather with extreme high pressure. See https://downdetector.co.uk/status/freeview/map/ I can’t suggest anything better than waiting for the weather to change. With a Freeview Play box you can at least use catchup to watch some of the programmes.