Unexpected HTTP response: 500

Request
{
    "operation" => "write-attribute",
    "address" => [
        ("subsystem" => "elytron"),
        ("key-store" => "testLKS")
    ],
    "name" => "new-item-template",
    "value" => {
        "new-item-attributes" => [
            "test1",
            "test2"
        ],
        "new-item-path" => "cesticka",
        "new-item-rdn" => "testRDN"
    }
}

Response

Internal Server Error
{
    "outcome" => "failed",
    "failure-description" => "WFLYCTL0201: Unknown attribute 'new-item-template'",
    "rolled-back" => true
}