I just used ufw to enable port 1337 on my Ubuntu system for the first time. After that, my instance was fine, but port 1337 was still not open, so I changed the security group from the ec2 console. After that, I rebooted the instance.
After that, I could not ssh anymore. I also tried to access port 80, which was previously open, but now it looks as if all ports are blocked.
How can I get my Shell access back?