In reply to Paul.

For a bit more info.... I have tried the cloud formation scripts that create the VPC and the scripts that deploy to an existing VPC and I am not using SSL and leaving those parameters blank.

Instance sizes are i3x2xlarge and r5.2xlarge and I have an email address added and get the notification email that says ansible has been provisioned. After that the instances build and then fail on post deployment steps.
For permissions for the Ansible and CAS servers is 0.0.0.0/0 and I am well within limits for vCPU and instance numbers.