diff --git a/src/main/java/org/codelibs/fess/exec/Crawler.java b/src/main/java/org/codelibs/fess/exec/Crawler.java
index ef7e9298b4..be2fa4434b 100644
--- a/src/main/java/org/codelibs/fess/exec/Crawler.java
+++ b/src/main/java/org/codelibs/fess/exec/Crawler.java
@@ -281,9 +281,9 @@ protected void sendMail(final Map<String, String> infoMap) {
             }
 
             try {
-                dataMap.put("hostname", InetAddress.getLocalHost().getHostAddress());
+                dataMap.put("hostname", InetAddress.getLocalHost().toString());
             } catch (final UnknownHostException e) {
-                // ignore
+                dataMap.put("hostname", "Unknown");
             }
 
             logger.debug("\ninfoMap: {}\ndataMap: {}", infoMap, dataMap);