Tomcat not accessible from EC2 Instance

I am not able to access the tomcat using public IP of EC2 Instance. I can access it using http://localhost:8080 internally but not from outside. In fact, It was running good since 2 months but suddenly it stopped and now I am hanging in between. locally my application is running fine and I can ping to my Instance using Public IP. Security group defines access to all traffic (TCP,HTTP,SSH). Then why Tomcat/Application is not being accessed externally. Any help will be highly appreciated. Thanks