Getting a 502 Bad Gateway response during the local testing of the container based lambda

I am following the example here https://pypi.org/project/awslambdaric/ . When I run the curl command to test the lambda I get no response. With the increased verbosity in the curl command I get the error 502 Bad gateway. The peculiar thing is that sending curl command again hangs - with the last message being "upload completely sent off: 2 out of 2 bytes". A standard docker nginx test works fine (something similar to https://www.docker.com/blog/how-to-use-the-official-nginx-docker-image/)