You must create the cluster peer relationship between the MetroCluster clusters.
Creating a cluster peer relationship
You can use the cluster peer create command to create a peer relationship between a local and remote cluster. After the peer relationship has been created, you can run cluster peer create on the remote cluster to authenticate it to the local cluster.
Creating a cluster peer relationship (ONTAP 9.2 and earlier)
You can use the cluster peer create command to initiate a request for a peering relationship between a local and remote cluster. After the peer relationship has been requested by the local cluster, you can run cluster peer create on the remote cluster to accept the relationship.