This is an old reply (2015) from the community , i copy this one because of i have the same issue
I'm facing some problems with the configurarion of QMC on Qlik Sense Server. The thing is, I am able to access QMC and Hub UNTIL I enable the proxy for accessing internet. The internet in the server I am working can only be enabled using a proxy on the 8080 port. The defauld listen port on QMC proxy is 80, but when I enable Internet proxy my Sense Server (QMC and HUB) turn off.