Problem: QR code isn't opening
Reason: The project URL is not accessible from the local machine.
Solution: 
Make the project URL accessible from the local machine.
If you're using iptables to redirect port 80 to 8080, redirect also for loopback interface:

# iptables -A OUTPUT -o lo -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 8080