It depends on several things from your geographic location (or your proxy's) to device issues (cache for example).
Try cleaning your device's data and cache for the game then try running the game again, if this doesn't solve the problem try using a proxy.
Also, there are already several threads addressing this issue. I suggest you to use the search function rather that opening new ones in the future, this to keep the forum clean and smooth.
Check this thread for further sugestions on you problem:
@Phantasmos, @Juketime if you please...