The http 500 error may be a result of a couple of things. One place you can look to see if everything proxy specific has started properly is the log located at %programdata%\qlik\sense\log\proxy\*System_Proxy.txt.
Have you been able to connect to the QMC? You need to connect to the QMC and license the server before attempting to connect to the hub.
Some of the likely causes are:
1. You are running a web server like IIS on the same system as Qlik Sense proxy and the two services are competing to listen on ports 80 and 443.
2. You have other software installed listening on ports 80 or 443.
3. Post installation the proxy service did not fire up completely. Reboot your system and see if that clears up your issue.