Error removing host interface declaration

[domain@localhost:9999 /] /host=master/interface=custom:remove       
{
    "outcome" => "failed",
    "result" => {"server-groups" => {"staging-server-group" => {"staging-server" => {
        "host" => "master",
        "response" => {
            "outcome" => "failed",
            "failure-description" => "JBAS014807: Management resource '[(\"interface\" => \"custom\")]' not found",
            "rolled-back" => true,
            "response-headers" => {"process-state" => "restart-required"}
        }
    }}}},
    "failure-description" => "JBAS010839: Operation failed or was rolled back on all servers.",
    "rolled-back" => true,
    "response-headers" => {"process-state" => "restart-required"}
}