The connected load does not switch. Only a click can be heard. What could be the cause?

Please check the electrical connection of the switch actuator. The Smart light receiver 1-channel is potential-free at the factory. Jumper L1 (230 volts) to the relay inputs. You can also switch other potentials with the Smart light receiver 1-channel, for example 12 volts for solenoid valves, loudspeaker signal for your garden loudspeakers or similar. Please refer to the connection diagram.