For safety reasons, the radio code for DuoFern actuators / tubular motors is only active for two hours* after the power is switched on. If the actuator / tubular motor has been connected to the 230V mains for longer than two hours, disconnect the power supply for approx. 10 seconds.
Note on the radio code: The radio code is only supplied with devices that are generally difficult to access, such as radio tubular motors, flush-mounted actuators, etc.