I installed Android Studio 2.2.2 on my system. After when I openend one of the projects which have compileSdkVersion 23, got following error,
If you were in China, maybe because of the host problem.
I had resolved this problem with 3 steps
the android sdk platform resources are download from host dl.google.com
so first step, get the available ip address for dl.google.com
(1) visit the ping tools
(2) get the 'best' ip address for dl.google.com
according to the pic best one is 203.208.41.73
(3) set the local host for your computer
(4) install sdk platform again
If you were in China hope this trick could help you