How can I fix “Design editor is unavailable until a successful build” error?

Question

I started to learn Android Studio from yesterday. I try to echo out simple \"Hello World\":

Answer 1

If you are in corporate setting where there is a proxy server, double check your proxy settings.

1. Go File -> Settings
2. Search for Proxy.
3. Fill out as appropreate.
4. Test connection.

If you think you fat-fingered the password, there is a Clear passwords button you can click to where you can re-enter your creds. HTH