diff --git a/application/src/main/java/org/thingsboard/server/service/mail/DefaultMailService.java b/application/src/main/java/org/thingsboard/server/service/mail/DefaultMailService.java
index c069ba6..a6c4f43 100644
--- a/application/src/main/java/org/thingsboard/server/service/mail/DefaultMailService.java
+++ b/application/src/main/java/org/thingsboard/server/service/mail/DefaultMailService.java
@@ -96,7 +96,7 @@ public class DefaultMailService implements MailService {
javaMailProperties.put(MAIL_PROP + protocol + ".port", jsonConfig.get("smtpPort").asText());
javaMailProperties.put(MAIL_PROP + protocol + ".timeout", jsonConfig.get("timeout").asText());
javaMailProperties.put(MAIL_PROP + protocol + ".auth", String.valueOf(StringUtils.isNotEmpty(jsonConfig.get("username").asText())));
- javaMailProperties.put(MAIL_PROP + protocol + ".starttls.enable", jsonConfig.get("enableTls"));
+ javaMailProperties.put(MAIL_PROP + protocol + ".starttls.enable", jsonConfig.has("enableTls") ? jsonConfig.get("enableTls").asText() : "false");
return javaMailProperties;
}