Hello, my Breville deep fryer has suddenly powered off because I moved it. What is the matter, please?

Some deep fryers have a magnetic quick release on the power cord. First, check to see if the power cord is securely fastened at the wall and at the base of the fryer.
Safety features of deep fryers include auto shut-off when oil overflows or reaches a certain vertical point in the fryer, or if there is too much or not enough oil. Drain the entire fryer and slowly refill it to the maximum fill line.
Some outlets, especially in bathroom and kitchen areas, have GFI (Ground Fault Interrupt) circuits which detect overload or short situations and shut off. You can see an example here. Ensure the "reset" button is pressed down. Another cause could be a tripped circuit breaker. Check the circuit breakers to ensure all of them are in the "on" position.