CANNOT INSTALL THE EXTENSION
Please see Chrome Help about this issue:
"If you see “NETWORK_FAILED” when you try to install an app, extension or theme from Chrome Web Store on Windows, unwanted software may be blocking the installation.
To fix the error:
First, remove the unwanted software. Then, try to install the app, extension or theme again.
If you still can't install the app, extension or theme, reinstall Chrome.