Failed to execute action [LCunrRXlStS-vH4o05YY8w_elasticsearch_nodes/send_email_to_admin] java.lang.IllegalArgumentException: no accounts of type [email] configured. Please set up an account using the [xpack.notification.email] settings

also make sure the information is available on all nodes (and the nodes are restarted), if you update the YAML file. Alternatively you could also use the cluster update settings API.

--Alex