I'm trying to create an AWS Cloud9 environment to access a DocumentDB server for direct access. However, when creating the Cloud9 environment it takes forever then dies with an error regarding an inability to connect to the functional backing EC2 instance. My VPC has 2 public and private subnets and no matter which subnet I use all of them fail with the same error. I have a web server running on the same VPC under one of the private subnets that can be accessed from the open internet perfectly fine and access my DocumentDB database. I have two NAT gateways, one hooked to each of my public subnets. I also have route tables set up to access the open internet. Is there something that could be obviously affecting the Cloud9 environment's ability to connect to it's EC2 instance?
It turns out that my private subnet route tables were misconfigured; they were forwarding 0.0.0.0/0 to an internet gateway, not to my NAT gateway.