yeelight cannot setup on iphone

Why the hell this thing cannot be setup on iphone? I have tried basically every steps that I can find on the internet. TF! Can someone help me? I’m getting annoyed by this stupid thing.
How the hell I can connect this stupid bulb to a network. My phone is connected to a hotspot, and when I go to the Yeelight app, it asks me to connect to Yeelight ssid, when I am already connected and trying to setup the device, stupid thing only reach 25% then it will automatically get disconnected from the stupid Yeelight SSID and will fail. Arghhhh waste of money.