Yeelight 480 - YLXD05YL failing to connect in App

I have installed and tried to set up the Yeelight 480 ceiling light. The bluetooth remote control works but when I try to connect the light in the Yeelight app it keeps failing at the Connecting stage. I select Add Device and select LED Ceiling Light M…, LED Ceiling Light Moon is shown in the list and then selected. It starts connecting but keeps failing at or around 15%. I have tried both the China and German Server. Can anyone help solve this as it is frustrating.

Please make sure if ceiling light connected to your router when the connection fails. You can check it from DHCP list in your settings page of your router.