I have a very simple Lambda function to return a JSON object. I've set up a trigger from API Gateway and I can see in the Lambda function overview that there is an API endpoint exposed here.

In API Gateway > APIs, I have a new REST API called hi-world, I have created a GET /hello-world resource. In the Test tab within this resource, when I test it I get a 200 response and the expected response body. It looks like there is a token being passed in the header as I can see Authorization=****** but I have authorization set to NONE in the method request tab.

I have created a custom domain name for my domain, the API Gateway Domain name is d-pwenhufonj.execute-api.eu-west-1.amazonaws. I have mapped this API to my hi-world API, to the dev stage, to the hello-world path and I have deployed it.

When I try and access this domain name with any combination of stages and paths I get a 403 response. I've set up an A record for my custom domain in Route 53 to point to the only API Gateway resource. However when I hit my custom URL I get {"message":"Missing Authentication Token"}.

Do I need to do something to allow the API Gateway to be accessed by the public? When I point my A record to an S3 bucket it serves as expected.