Starting from April 17, 2019, the security policy of ACK for managing the permissions required to access a Kubernetes cluster are upgraded. After this release, the upgrade security policy denies any cluster accesses performed by RAM users not granted with the required permissions. That is, RAM users can only access the Kubernetes clusters for which they have been granted the required permissions.
You must grant the required RAM permissions to all the RAM users under your management for them to access corresponding clusters. For more information, see Create custom authorization policies.