Please find my comments inline
bitnami@ip-172-31-29-57:~$ ssh email@example.com
bitnami@ip-172-31-29-57:~$ means you are already connected to your server using the user bitnami. Why are you running an SSH command from there?
The authenticity of host '' can't be established.
RSA key fingerprint is 6c256:pN3PEfkIdd16E5XzKhIarNSFhAT/Yr3RSBGbtSbRPEk.
Are you sure you want to continue connecting (yes/no)? Yes
Can't connect to server
(Cause Auth fail)
Did you configured NetBeans to use the SSH key you use to connect to your server using PuTTY? It should work fine if you are using that key. Can you ask for help on how to debug this error in the NetBeans official forum? Note they ca provide you with a better support on their product than we can