I've been getting this on my Samsung tablet this morning. In order to connect to any site I need to turn wi fi off and on again. It's also affecting another tablet and 4g phone.
No broadband issues according to Virgin.
Go to settings > WiFi > press and hold the connection you have issue with > modify network > tick advanced options > IP Settings drop down > select Static > enter the IP address you want, gateway (your routers IP address), DNS1 and DNS2 (find them in google).
Yes, I am agree with bhg481. I met this before. You can turn off your wireless router or directly plug out the router power for several minutes , and then reboot the wireless router. After that, when you reconnect the wifi, the exclamation will disappear.