Fixed build issue in logs

Author: karthik-tarento

notification-sdk/src/main/java/org/sunbird/notification/email/Email.java

@@ -273,7 +273,13 @@ private boolean sendEmail(Session session, MimeMessage message) {
       transport = getTransportClient(session);
       transport.sendMessage(message, message.getAllRecipients());
     } catch (Exception e) {
-      logger.error("SendMail:sendMail: Exception occurred while sending message = " + message.getContent().toString(), e);
+      String msgContent = "";
+      try {
+        msgContent = message.getContent().toString();
+      } catch (Exception e1) {
+        logger.error("Failed to retrieve the content from message.", e1);
+      }
+      logger.error("SendMail:sendMail: Exception occurred while sending message = " + msgContent, e);
       response = false;
     } finally {
       try {