I have here following JS code to fetch the balance of an ethereum address

async function getBalance() {
  document.getElementById("whoohoo").innerHTML = address;
  const response = await fetch('https://deep-index.moralis.io/api/v2/' + address + '/balance?chain=bsc', {
    method: 'GET',
    headers: ({
      'accept': 'application/json',
      'X-API-Key:': 'api key goes here'
    })
  })
  console.log(await response.json())
}

But instead of getting the balance i get following error:

Uncaught (in promise) TypeError: Failed to execute 'fetch' on 'Window': Invalid name
    at <anonymous>:1:876
    at getBalance ((index):38)
    at HTMLButtonElement.login ((index):33)

I assume there is something wrong with the headers but im not quite sure about that. How cvan i fix this?

I have tried to change it to

headers: new Headers({
                    'accept':'application/json',
                    'X-API-Key:':'api key'
                })

and than i get

Uncaught (in promise) TypeError: Failed to construct 'Headers': Invalid name