Ultra High Performance for boot volume

Hello,

I have updated my boot volume to 120 VPU but when typing this in the CLI I get authentication error

oci bv volume update --volume-id ocid1.instance.XXXXXX --vpus-per-gb 120

I get the following error:

ServiceError:

{

  "code": "NotAuthorizedOrNotFound",

    "message": "Authorization failed or requested resource not found.. Please visit https://docs.oracle.com/en-us/iaas/Content/API/References/apierrors.htm to learn more about this error code",

  "opc-request-id": "****",

  "status": 404

}

What am I doing wrong? and is the volume update neccessary or would it update automatically if I reboot the instance?

Thanks in advance!