There are actually quite a range of ports you may need to open up. We've found that we needed to have 443, 80, 4244 and 4248 that you have, but also 4241, 4242, 5050 and 5051 when deploying to AWS. One of my colleagues, chris_johnson has done a fair bit of work on this and may be able to advise further.
unfortunately open the ports on AWS load balancer do not sort the expected result.
Enabling firefox Firebug report this error:
Firefox can't establish connection with server wss://qliksense.techedgegroup.it/app/engineData?reloadUri=https://qliksense.techedgegroup.it/hub/?qlikTicket=XXXXXXXXXXXXXXX
Any clue ?