Yeelight Bulb E27 don't works

Hi, I got a one Yeelight bulb and it isn’t connect to my Iphone SE. My Router is ZTE ZXHK F670 (it works on 2.4Gz and 5Gz).
I tried to connect not through the router (by another iphone with modem-mode) and bulb is WORKS.
So I see the problem in router or it can be in bulb (Iphone perceive Bulb as “Unsecured network”) and I don’t know how to fix it.
Please help with router settings or smth else

The bulb can only work on 2.4G. If your 2.4G and 5G share the same ssid, try to separate them and use 2.4G.

There are two wifi names with 2,4 and 5gz. Yes I use to 2,4gz and it isn’t work. 25% and “connections lost, try again”

Try changing your Wi-Fi security method to WPA/WPA2-PSK.