Hello there
My name is Chris Schuck. I work as an Infrastructure Administrator for a company heavily reliant on AWS for running our Cloud based software, and so have a thorough understanding of security in AWS. The communication problem which you are experiencing is likely to be in the routing tables in the VPC portion of AWS, and I would be glad to help you out.
If you are able to provide me access to your AWS console, I should be able to correct the communication problem within a couple of hours at most.
This being only my second bid through Freelancer, I have no previous history which you can reference to help my bid unfortunately, but I hope you consider me to help fix the problem.
Regards
Chris Schuck