I have an iphone 4s running ios 9.3.5 and i connected to my Wi-Fi to download an app then i got half through when my Wi-Fi greyed out?

I have an iphone 4s running ios 9.3.5 and i connected to my Wi-Fi to download an app then i got half through when my Wi-Fi greyed out?

Shutdown the phone and restart, if the Wi-Fi remains grey then the Wi-Fi chip may have died.