@andrewbeniston71
I doubt they just say error; they probably say more than that, with codes you can look up on the YouView website, and try the actions indicated.
But if none of them work, try any other online services the set might have, like YouTube or Netflix.
And if nothing works, check you have internet connectivity to the set at all, and set it up if not.
If you can’t, or if these other online services work OK, then carry out a Factory Reset, and report back if this is successful or not.
My favourite bedtime reading is a Sony product manual…
