I always get an error when I try to use the Launchpad installer. My host said, that the hosting is ok an also localhost is the right writing for MySQL Database. But your system says, that there is a problem.
Please have your host whitelist the following main IP address: 220.127.116.11 and ensure that fsockopen() is not disabled. One way that works consistently is the option to download the file and run the installer from your cPanel as in the video below…