Unable to read server resources

[domain@localhost:9999 /] /host=master:read-children-resources(child-type=server,recursive=true)
{
    "outcome" => "success",
    "result" => {}
}

[domain@localhost:9999 /] /host=master:read-children-names(child-type=server)                                      
{
    "outcome" => "success",
    "result" => ["server-one"]
}