And it can ping it on the (Wifi) network (through NetScan app added device with hue syncbox IP-adres ) ??
Do you use only wifi or also the usb lan adapter for your Homey pro ??
Something must be different in the connection specs between the Homey Pro and your phone.
Same Wifi 
? Same Wifi frequency 2.4 GHz/5GHz ?
Same local network subnet?
I’m not sure but the Hue syncbox app might connect directly through Bluetooth to the syncbox and not through wifi. Maybe try it by disabling Bluetooth on your phone and the try the Hue syncbox app on your phone. 
