Unable to migrate from express-graphql: loads forever

[Zhepu-zingbox]

Screenshot

Expected Behaviour
Should return

{
    "data": {
        "hello": "world"
    }
}

Actual Behaviour
Check screenshot, loads forever.

Debug Information
I used 2 code snippets: one with express-graphql, the other graphql-http

const express = require("express")
const {createHandler} = require('graphql-http');
const { GraphQLSchema, GraphQLObjectType, GraphQLString } = require("graphql");

const schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: 'Query',
    fields: {
      hello: {
        type: GraphQLString,
        resolve: () => 'world',
      },
    },
  }),
});

const app = express()
  app.use(
  "/graphql",
  createHandler({
    schema
  })
)
app.listen(4000)
console.log("Running a GraphQL API server at http://localhost:4000/graphql")

const express = require("express")
const { graphqlHTTP } = require("express-graphql")
const { GraphQLSchema, GraphQLObjectType, GraphQLString } = require("graphql");
const schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: 'Query',
    fields: {
      hello: {
        type: GraphQLString,
        resolve: () => 'world',
      },
    },
  }),
});

const app = express()
app.use(
  "/graphql",
  graphqlHTTP({
    schema: schema
  })
)
app.listen(4000)
console.log("Running a GraphQL API server at http://localhost:4000/graphql")

Further Information
I'm with node v16.16.0
package.json

{
  "name": "demo",
  "version": "1.0.0",
  "description": "demo",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "license": "ISC",
  "dependencies": {
    "express": "^4.18.2",
    "express-graphql": "^0.12.0",
    "graphql-http": "^1.18.0"
  }
}