ARI connection problem

I am using ARI using python and stasis application. I am using ARI and asterisk application on amazon ec2 instance. This is the code being used for ARI. I am facing a connection issue as whenever i am trying to connect the ARI application to asterisk it gives no error, but on asterisk logs the ARI app doesn’t get registered. While making a call, asterisk log gives an error “bridge-dial not registered”.

But when i try to connect to asterisk running on a different ec2 instance the ARI connects without any problem. Even if I am stopping the asterisk on my instance ARI still connects to asterisk, but it gives an error when the asterisk of other instance is down.

It works on one asterisk instance and does not work on a different instance?
You need to look at the difference between these two instances.

All configurations files in both the instances are the same. There is no difference in the asterisk config files.

By instance, I meant the whole system. OS settings, selinux, asterisk setting, etc…

Since one EC2 instance is working, have you tried cloning the working instance?
Make an exact copy of the working instance, followed by the appropriate network changes.