Since getting the recent Lollipop upgrade, the wifi symbol always has an exclamation mark. Wifi seems to work fine, and I gather this symbol means something to do with inability to access Google services - but I use Google Inbox, and that works fine, too. I also understand that this symbol corresponds to the red-shaded wifi symbol of Kit-Kat, but I didn't have that persistently.
So what's going on? It's just slightly annoying.
Motorola Moto G, early 2014.