Specify the proxy server as part of the instance configuration in Amazon AWS. You'll enter proxy settings in the User Data field - the same field where you enter the personalization code.
If you have a domain user, the format is domain\username:password@proxyhost:port
If authentication is not used, the format is proxyhost:port
proxyhost is the IPv4 address or the FQDN of the proxy server.
You'll need to go to your AWS instance and stop it. Then update the User Data field with updated proxy information.
Have a proxy server for connecting to your Amazon EC2 API endpoints? If yes, you can edit your scanner appliance in the Qualys UI to provide details about the proxy server. Enter the proxy server's hostname and/or IP address, port, and authentication credentials (if required by the proxy server).
You must allow the EC2 Region endpoints to be accessible via the proxy. Identify the URL to an endpoint from here - http://docs.aws.amazon.com/general/latest/gr/rande.html#ec2_region
You'll see No Host Alive in your scan results if the proxy is not set up correctly or the proxy server is down.