Ceiling lamp connection to app / server

Hi, i have some color bulbs and also several ceiling lamps. From the beginning i was not able to connect them by choosing ceiling lamp in the apps (yeelight and Mi Home). Instead i have to choose color bulb and then connect first with the device and then with my network.
The newest ceiling is the 650 which after installed i was able to connect on the same way. Today i connected the ceiling lamp to remote control as well. After i did this, the lamp was disconnected to the sever and i could not reach anymore by with the apps.
Several tries to re-connect the ceiling lampe, or on Singapur and Mainland failed. After changed the WIFI of the device i cannot get any connection between the iphone and the device.
I resetted the device many many time but always the same problem.
All other devices are working well.

Any idea what i can try.

Thanks, Simon

Sorry for the issue, please let us know which step do you stuck?

And at last please use another phone to setup a hotspots with 4G network and try connect the bulb to it, I want to make sure if the bulb is ok. Thanks!

After i switched from the WIFI setting, where i choose the ceiling lamp WIFI, i went back to the Yeelight app and the percentage remains always 0%.

I have another ceiling lamp very closed in a room, only around 2meters. Could this be a problem ?

When back home i will try to connect with a hotspot as well.

Could you use an Android phone to have a try?

No, we only use Apple devices. But i have another 3 ceiling lamps and bedside lamps and bulbs. Only this 650 ceiling is not working properly.

Was able to connnect the ceiling by using yeelight app on an ipad with a LTE hotspot from my iphone. It works until i close the hotspot. Then the lamp is offline if i switch to my home WiFI and also if i use the app on my Iphone with LTE as well. Means only Online if i go over the hotspot. Any idea ?

Maybe you can setup a hotspots with the same SSID and password as your home wifi.