Wifi itself worked on my flight yesterday (3-class 777) but no Internet or PDE, only mobile app and UA web site worked. The one time I really needed to VPN in to work on the plane and it didn't work. FA said it's just intermittent and to keep trying. I tried for the whole flight, never managed to get the unitedwifi.com page to come up and PDE through the app just opened up the regular UA Inflight WIFi web page. Very frustrating.