Internet is connected, but destination host unreachable
destination host unreachable
is a generic response to an unsuccessful ping that indicates that there is a problem with internet connectivity. If you have wireless connectivity in other devices that means that the wireless settings on your router are configured correctly.
Check if you have wireless connectivity on your phone. If not, restart your router by turning off the router, waiting 10 seconds and then turning it back on. I've had an opportunity to test toggling the router power button off/on when I discovered that the wifi was disconnected on two different devices, and toggling the router power button off/on allowed the wifi to be reconnected automatically on both devices. Sometimes it takes a minute or two for the router to completely restart at which time the indicator lights in the front panel of the router should be lit as they normally are.
If restarting the router doesn't work maybe there is a internet connectivity problem originating from outside your home. If the problem persists then phone your internet service provider for help.