Hi Jon
search for the manual on the angel homebrew Brew Devil, it shows the err1 is temp lower than -20 which I don't think its that so it also says that the sensor is loose or need reconnecting.
I am not saying it is 100% that but they are the same machine initially as the Ace so it should apply.
Ps make sure before opening the bottom up to check the sensor that it is unplugged from the mains