Basically, no device that is registered with the HomePilot® is enabled for voice control.
Please ensure that voice control is enabled in the device settings of the device. Call up the device in the HomePilot app and call up the configuration.
In the device settings section, you will find the "Voice control" item. Activate Alexa and then say "Alexa, find my smart devices".
The device will then be addressed with the actual name of the device. Therefore, please make sure that the names are unique. Names must not be assigned twice, otherwise Alexa will not be able to distinguish between the devices. Ultimately, you will have to test out which names are most suitable in practice.