Serverless | How to set Lambda authorizer to None (public API)

Please consider the following code (serverless.yml):

functions:
  exportCvToPdf:
    handler: handler.exportCvToPdf
    timeout: 20
    events:
      - http:
          path: export
          method: post

Deploying to AWS returns a link to the API endpoint. CURL'ing the endpoint returns:

{"message":"Missing Authentication Token"}

How can I make a public endpoint using Serverless Framework?

I have tried the following:

functions:
  exportCvToPdf:
    handler: handler.exportCvToPdf
    timeout: 20
    events:
      - http:
          path: export
          method: post
          authorizer: none # None NONE "none" "NONE" "None" has also been tried

The above returns an error at deploy:

Function none doesn't exist in this Service