Xiaomi Router 3 Global Version keep disconnecting

[TheGemer]

I just got new connection from an local ISP. I am using xiaomi router 3 global version. I've setup everything correctly. When I connected first time to the Wi-Fi it was working fine but after sometime it disconnected i was to reconnect but the Wi-Fi name disappeared. After some time it reappears and automatically reconnects. This keep happening. Only 2.5 GHz and is on, I've tried to reset and re-setup the router but same as before. I've also updated the router firmware to the latest version. But if its connected through Ethernet cable it works fine. The problem is with the Wi-Fi.