});
                } catch (final Exception e) {
                    logger.warn("Failed to send a test mail.", e);
                } finally {
                    SMailCallbackContext.clearPreparedMessageHookOnThread();
                }
            }
            resultBuf.append("Status of ").append(ping.getClusterName()).append(" is changed to ").append(ping.getClusterStatus())
                    .append('.');