@vsparihar 

Hello, thanks for reporting the issue to the community, can I have more details then our engineers can try to investigate further?
1. Is the wired connection of this A20 is unstable or both wired and wireless are not stable? May I know how many devices are connected to the A20, wired and wirelessly, 2.4GHz and 5GHz? Is the internet LED on the A20 green or orange when it disconnects?
2. Are all of them experiencing the same dropout or just some special or old clients? When they got disconnected, is the wireless network of the Archer A20 still broadcasting or the wireless network is no longer available on all other devices as well?
If the devices are still connected to the 2.4GHz/5GHz network but no internet access, please confirm if the devices can still get a correct IP address from A20, what is the IP address? Can you ping the A20 gateway and internet? How to do this? Click here.
If the devices disconnected from the wireless and cannot connect back, what is the error message?

3. Who is your ISP? What is the model number of the modem? Ensure the modem is stable, you may connect a computer to the modem directly and confirm.