Could not determine artifacts for

Hi, my project was working fine before, but suddenly have issue when building

> What went wrong:
Could not resolve all dependencies for configuration ':app:debugCompileClasspath'.
> Could not determine artifacts for
> Could not get resource ''.
> Could not HEAD ''.
> Connect to [,,,] failed: Operation timed out (Connection timed out)

Can anyone help me to figure out why? i havent made any major changes or havent install new plugins.

I have trie removing and adding platform. and also uninstall/install facebook-plugin but the issue persist.