diff --git a/src/main/java/edu/harvard/iq/dataverse/GuestbookResponse.java b/src/main/java/edu/harvard/iq/dataverse/GuestbookResponse.java
index 1eea1f3ac7d..830c7740e34 100644
--- a/src/main/java/edu/harvard/iq/dataverse/GuestbookResponse.java
+++ b/src/main/java/edu/harvard/iq/dataverse/GuestbookResponse.java
@@ -200,7 +200,8 @@ public String getEmail() {
     }
 
     public void setEmail(String email) {
-        this.email = email;
+        // ValidateEmail requires NULL or valid email. Empty String will fail validation
+        this.email = (email == null || email.trim().isEmpty()) ? null : email;
     }
 
     public Guestbook getGuestbook() {