Cannot read property 'Access-Control-Request-Headers' of undefined

[incompletude]

I have found this issue, related to mine, but I could not found a solution to my problem.

#1560

serverless.yml:

service: graphql-aws

provider:
  name: aws
  runtime: nodejs8.10
functions:
  graphql:
    handler: graphql.graphqlHandler
    environment:
      SLS_DEBUG: true
    events:
      - http:
          path: graphql
          method: post
          cors: true
          integration: lambda-proxy
      - http:
          path: graphql
          method: get
          cors: true
          integration: lambda-proxy

graphql.js:

const { ApolloServer, gql } = require('apollo-server-lambda')

const typeDefs = gql`
  type Query {
    hello: String
  }
`

const resolvers = {
  Query: {
    hello: () => 'Hello world!',
  },
}

const server = new ApolloServer({ typeDefs, resolvers })

exports.graphqlHandler = server.createHandler({
  cors: {
    origin: '*',
    credentials: true,
  },
})

Test:

serverless invoke local --function graphql --data '{ "httpMethod": "POST", "body": { "query": "{ hello }" }}'

Error:

Cannot read property 'Access-Control-Request-Headers' of undefined

Can someone help me solving this?