API Gateway "blocked by CORS policy" when using Cognito User Pool Authentication

Question

I have a REST API that triggers a Lambda function to return some data from a DynamoDB table. Everything was working when I had no authorization in the process with my fetch statement looking like:

function fetchData(){
  const itemID = encodeURIComponent('item#123');
  const url = "https://domain1234.execute-api.region.amazonaws.com/stage/item/" + itemID;
  fetch(url)
  .then(response =>{
    return response.json()
  }).then(jsonData =>{
    console.log(jsonData)
  }).catch(e =>{
    console.log(e.message)
  })
}

I then included authorization through Cognito with the following steps.

1. I added the pool as an Authorizer in the "Authorizers" section of API Gateway. Setting the token source as "Authorization"

2. Tested the Authorizer using a Cognito idToken after logging in and pasting into the test. The test was successful.

3. Set each method to use that Cognito pool.

When I re-write the fetch to include a Authorization header I get a failed to fetch error.

The updated fetch is as follows:

function fetchData(){
  const itemID = encodeURIComponent('item#123');
  const url = "https://domain1234.execute-api.region.amazonaws.com/stage/item/" + itemID;
  fetch(url,{
  headers: {"Authorization":"myVeryLongIdToken"}
})
  .then(response =>{
    return response.json()
  }).then(jsonData =>{
    console.log(jsonData)
  }).catch(e =>{
    console.log(e.message)
  })
}

I get the error:

has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled. Does this mean my API request is blocked at the API Gateway level and not being authorized?