I have problem connecting to any WiFi after upgrading to OS X El Capitan on Macbook Air - 2014. I have done all I can but nothing seems to be working even resetting the router. My iPhone and iPad are connecting but not macbook. I have also restored from time machine backup with Yosemite and WiFi worked with no problem. Now I have reinstalled El Capitan and WiFi problem is back. Any ideas fixing the issues.