I've tried to download windows x64 version through Google chrome and Mozilla but I cannot get it. Always I get a "network issue". My connections is fine as I can download several files from other sites. What can I do?

Before you pick the installer file, at right corner (down) you see a message about issues to start to download the file. Click there and you see the Enable alternate download mode option

For me stopping it every 5 mb and then resuming it after 1-2 seconds worked. You can try that 2.