Sometimes,whatsapp doesn't connect over wifi...?

[Ruturaj]

I connect to wifi and I have to login the internet. When I do login,sometimes whatsapp just instantly connects and I start receiving notifications. But sometimes,it just doesn't connect. I try refreshing favorites, sometimes it works,but most of the time, wifi gets disconnected. I have to connect to wifi again,but still it won't work sometimes. The network range is good.
Also,is there any way I can increase the network range of the router?

[Mr. Tech]

Probably its because of weak WiFi signals so the best way to increase the WiFi range is to get an WiFi repeater or signal booster which shall increase your signal coverage area.