It says that the server unexpectedly dropped the connection. It says that this is most likely because the server is busy and to try again later. I’ve been trying for three days.
They’re the people you pay monthly or annually to host your site.
Did you setup this site yourself? If so, picking a hosting provider is basically the first step. You can’t install WordPress on a hosting provider without a hosting provider. If someone else set up the site for you, then contact them immediately.