API Gateway Custom Domain Name getaddrinfo ENOTFOUND

I have created an api using AWS API Gateway and would like to attach a custom domain name to it. I followed this tutorial and have done the following:

1. Created new certificate on Certificate Manager (mydomain.io and *.mydomain.io)
2. Added CNAME to GoDaddy (since mine was purchased from Godaddy)
3. Set up a api-dev.mydomain.io on API gateway > Custom domain names, and mapped it to the API and dev stage in the "API Mappings".
4. On Route 53, added api-dev.mydomain.io as an A record and direct it to the API (the API domain name is correct) in step 3.

I believe that my setup should be correct to the best of my knowledge, and have waited 1 hour for it to "take effect".

I then write a simple script to test it but it throws the above error.

Code:

const axios = require("axios")

let baseUrl = "https://api-dev.mydomain.io"
let key = MY_API_KEY
let headers = {
    headers: {
        "x-api-key": key
    }
}

let usersEndpoint = baseUrl + '/token?email=someemail@gmail.com'

axios.get(usersEndpoint, headers)
.then(response => {
    let data = response.data
    console.log(data)
})
.catch(err => console.log(err))

Error message:

Error: getaddrinfo ENOTFOUND api-dev.mydomain.io
    at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:66:26) {
  errno: 'ENOTFOUND',
  code: 'ENOTFOUND',
  syscall: 'getaddrinfo',
  hostname: 'api-dev.mydomain.io',
  config: {
    url: 'https://api-dev.mydomain.io/token?email=someemail@gmail.com',
    method: 'get',
    headers: {
      Accept: 'application/json, text/plain, */*',
      'x-api-key': MY_API_KEY,
      'User-Agent': 'axios/0.21.1'
    },
    transformRequest: [ [Function: transformRequest] ],
    transformResponse: [ [Function: transformResponse] ],
    timeout: 0,
    adapter: [Function: httpAdapter],
    ...

What am I missing?