Hi

I've setup a brand new C3150 router. All the wired connections works perfectly. My issue is with Wi-Fi connected devices. We connect them to the router but Internet access goes on and off randomly. Our smartphones stay connected but we have ! appearing on status bar some seconds and disappeared after some seconds / minutes. We see this on many devices. I figured that wireless device stay connected to the wireless network but seems to lost routing to Internet. When this happen, I can't browse the internet but I'm able to connect to router through Tether app without any issue. 

I'm looking for any input on router configuration that could cause this.

If someone can help with this, it would be really appreciated. 

Thanks