Feedback for “Checkouts”

when I call the API i got error code 401 not authorized and the json response is {"title":"Checkout not found","type":"about:blank","status":401,"detail":"Checkout Id `20806c49-5169-48e3-8032-13143568f7ab` does not exist"}

please advise what is the correct authorization for this store front API https://developer.bigcommerce.com/docs/rest-storefront/checkouts#get-a-checkout

