Repository_verification_exception

Hi All.
I manage few ES clusters that perform snapshots on S3 bucket without issues, they are all configured with master nodes and hot-data nodes.

Now, I have 1 cluster where we configured also warm nodes, and it seems that these warm nodes cannot register for the S3 repository. They do have the S3 plugin installed, and I verified installing the AWS CLI that the S3 bucket is reachable in r/w mode, as all other nodes.
Nevertheless this is the error that shows up in DevTools when I create the repository

    PUT /_snapshot/komgo-s3-repository
    {
      "type": "s3",
      "settings": {
        "bucket": "blablabla",
        "endpoint": "s3.eu-west-1.amazonaws.com",
        "server_side_encryption": true,
        "buffer_size": "64mb",
        "max_snapshot_bytes_per_sec": "100mb"
      }
    }

output:

    {
      "error" : {
        "root_cause" : [
          {
            "type" : "repository_verification_exception",
            "reason" : "[komgo-s3-repository] [[HhPYTqw7R9WMYaGZiP5K3w, 'RemoteTransportException[[elastic-es-data-warm-eu-west-1c-0][10.0.150.46:9300][internal:admin/repository/verify]]; nested: RepositoryMissingException[[komgo-s3-repository] missing];'], [XEVxl3NoR_S706KZxwkFHQ, 'RemoteTransportException[[elastic-es-data-warm-eu-west-1a-0][10.0.27.39:9300][internal:admin/repository/verify]]; nested: RepositoryMissingException[[komgo-s3-repository] missing];'], [uLafVN69Qqu__TmxSrFRiQ, 'RemoteTransportException[[elastic-es-data-warm-eu-west-1b-0][10.0.71.190:9300][internal:admin/repository/verify]]; nested: RepositoryMissingException[[komgo-s3-repository] missing];']]"
          }
        ],
        "type" : "repository_verification_exception",
        "reason" : "[komgo-s3-repository] [[HhPYTqw7R9WMYaGZiP5K3w, 'RemoteTransportException[[elastic-es-data-warm-eu-west-1c-0][10.0.150.46:9300][internal:admin/repository/verify]]; nested: RepositoryMissingException[[komgo-s3-repository] missing];'], [XEVxl3NoR_S706KZxwkFHQ, 'RemoteTransportException[[elastic-es-data-warm-eu-west-1a-0][10.0.27.39:9300][internal:admin/repository/verify]]; nested: RepositoryMissingException[[komgo-s3-repository] missing];'], [uLafVN69Qqu__TmxSrFRiQ, 'RemoteTransportException[[elastic-es-data-warm-eu-west-1b-0][10.0.71.190:9300][internal:admin/repository/verify]]; nested: RepositoryMissingException[[komgo-s3-repository] missing];']]"
      },
      "status" : 500
    }

Any idea?