Prometheus, set remote write to Amazon Manage Prometheus

I need to configure an ec2 instance as a scrape to monitor all instances created in a region. I understand that the scrape can monitor instances by the tag or by the instance id, so I have created the following configuration.

global:
  scrape_interval: 15s
  external_labels:
    monitor: 'prometheus'

scrape_configs:
  - job_name: test-dev
    ec2_sd_configs:
    - region: us-west-2
      secret_key: "xxxxxxxxxx"
      access_key: "xxxxxx"
      port: 9404
      filters:
        - name: instance-id
          values:
            - i-xxxxxxxxxxxxxx

remote_write:
  - url: https://aps-workspaces.us-west-2.amazonaws.com/workspaces/ws-xxxxxxxxxxx-b0d3-4cfe-b04d-xxxxxxxxxx/api/v1/remote_write
    queue_config:
        max_samples_per_send: 1000
        max_shards: 200
        capacity: 2500

I am using as a remote write workspace created on Amazon Prometheus through an IAM role with AmazonEC2ReadOnlyAccess and AmazonPrometheusRemoteWriteAccess permissions.

when running prometheus I see the following error:

ts=2022-08-09T20:07:45.931Z caller=dedupe.go:112 component=remote level=error remote_name=662c9f url=https://aps-workspaces.us-west-2.amazonaws.com/workspaces/ws-xxxxxxxx-b0d3-4cfe-b04d-xxxxxxxxxx/api/v1/remote_write msg="non-recoverable error" count=5 exemplarCount=0 err="server returned HTTP status 403 Forbidden: {\"message\":\"Missing Authentication Token\"}"

any helps??