I found a temporary solution for people having this problem.
You can start your AVD in CMD prompt like this
Windows
C:\program files\android\android-sdk-windows\tools\emulator -avd <avdname> -dns-server 8.8.8.8
Mac
cd ~/Library/Android/sdk/emulator
./emulator -avd <avdname> -dns-server 8.8.8.8
8.8.8.8 is google public DNS.
The problem seems to be that the emulator can’t find the DNS your computer is currently using.