diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/ws/common/impl/DateConverter.java b/navalplanner-webapp/src/main/java/org/navalplanner/ws/common/impl/DateConverter.java
index db9cbc4c1..4a179d76c 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/ws/common/impl/DateConverter.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/ws/common/impl/DateConverter.java
@@ -129,6 +129,9 @@ public class DateConverter {
     }
 
     public static XMLGregorianCalendar toXMLGregorianCalendar(Date date) {
+        if(date == null) {
+            return null;
+        }
         return toXMLGregorianCalendar(LocalDate.fromDateFields(date));
     }