diff --git a/META-INF/KeySpace Structure.xlsx b/META-INF/KeySpace Structure.xlsx
index fd70642..f470200 100644
Binary files a/META-INF/KeySpace Structure.xlsx and b/META-INF/KeySpace Structure.xlsx differ
diff --git a/src/main/java/org/gcube/portal/databook/server/DBCassandraAstyanaxImpl.java b/src/main/java/org/gcube/portal/databook/server/DBCassandraAstyanaxImpl.java
index 634ed8a..e29522d 100644
--- a/src/main/java/org/gcube/portal/databook/server/DBCassandraAstyanaxImpl.java
+++ b/src/main/java/org/gcube/portal/databook/server/DBCassandraAstyanaxImpl.java
@@ -1603,7 +1603,7 @@ public final class DBCassandraAstyanaxImpl implements DatabookStore {
 	 * {@inheritDoc}
 	 */
 	@Override
-	public InviteOperationResult saveInvite(Invite invite) throws AddressException, NullArgumentException {
+	public InviteOperationResult saveInvite(Invite invite) throws AddressException {
 		if (invite == null)
 			throw new NullArgumentException("Invite instance is null");
 		String email = invite.getInvitedEmail();
diff --git a/src/main/java/org/gcube/portal/databook/server/DatabookStore.java b/src/main/java/org/gcube/portal/databook/server/DatabookStore.java
index 2100a07..0ed3dae 100644
--- a/src/main/java/org/gcube/portal/databook/server/DatabookStore.java
+++ b/src/main/java/org/gcube/portal/databook/server/DatabookStore.java
@@ -365,7 +365,7 @@ public interface DatabookStore {
 	 * @param invite the invite object instanc to save
 	 * @return {@link InviteOperationResult}  SUCCESS, FAILED or ALREADY_INVITED (if an invite is sent to en existing email in the same environment more than once)
 	 */
-	InviteOperationResult saveInvite(Invite invite) throws AddressException, NullArgumentException;
+	InviteOperationResult saveInvite(Invite invite) throws AddressException;
 	/**
 	 * 
 	 * @param vreid the environment where you want to check the invite