Hi, I tried to open port 3306 for MySQL on the default security group, and I tried to create another security group with port 3306 in the inbound rules allowed with source "anywhere" but it results closed anyway.
I tried to check with this tool: https://www.yougetsignal.com/tools/open-ports/
I tried typing in the URL of my browser:"[EC2_PUBLIC_IP]:3306" but it denied the connection.
A time ago, I opened port 8080, and it worked. I added a new security group with this port allowed.