What is the reason for JWT Authentication Required error? - jwt

Question

I have created a JWT using the guide at the end of the page. However, when I make a request, I get back the code "AuthenticationRequired" and the message "Authentication required." I have verified that it is a valid JWT with RS256 algorithm. What could be the reason for the JWT to not be recognized?
I am able to make the same request with an access token but not JWT. I am using jsonwebtoken npm library, but I have also used PyJWT and received the same error.
Edit: JWT does work for Google Cloud Storage.
curl --request GET \
--url <https://storage.googleapis.com/{bucket}/{path}> \
--header ‘Authorization: Bearer <JWT>’ \
--header ‘Content-Type: text/plain’
jwt code:
var jwt = require('jsonwebtoken');
const acc = '<service-account-email>'
const iat = Math.floor(new Date() / 1000)
const exp = Math.floor(iat + (365 * 86400))
const PRIVATE_KEY_ID_FROM_JSON = '<key-id>'
const PRIVATE_KEY_FROM_JSON = '<private_key_from_json>'
const additional_headers = { 'kid': PRIVATE_KEY_ID_FROM_JSON }
const token = jwt.sign({
'iss': acc,
'sub': acc,
'aud': 'storage.googleapis.com',
'iat': iat,
'exp': exp
}, PRIVATE_KEY_FROM_JSON, { header: additional_headers, algorithm: 'RS256' });