issue Connection with EC2 Instance connect

I managed to connect to the instance via "EC2 instance connect" but by inserting "0 - 65535" as port ranges in the Security Group instead of 5071. Why was I able to connect before even having set 5071 and now I can't? I also noticed that if I create an Instance from another area, for example Ohio, inserting the "default" Security Group, it gives me the exact same problem and doesn't let me connect to my instance from Istance Connect. Why does this happen?