In case of network congestion or erratic Internet connection from the ISP, sometimes this does not work properly as the installation files doesn't get downloaded completely. We recommend to download and install offline installer package
Download manager software
Some download software manager's do not work properly and may interrupt or slow down the process. It is recommended to stop these third party download managers and start normal download.
Anti virus programs have options of not allowing the download, unless they are deactivated for that period.