diff --git a/src/java/davmail/exchange/ews/EwsExchangeSession.java b/src/java/davmail/exchange/ews/EwsExchangeSession.java
index 986bd795..a884c83d 100644
--- a/src/java/davmail/exchange/ews/EwsExchangeSession.java
+++ b/src/java/davmail/exchange/ews/EwsExchangeSession.java
@@ -2532,7 +2532,8 @@ public class EwsExchangeSession extends ExchangeSession {
     protected static boolean isItemId(String itemName) {
         return itemName.length() >= 152
                 // item name is base64url
-                && itemName.matches("^([A-Za-z0-9-_]{4})*([A-Za-z0-9-_]{4}|[A-Za-z0-9-_]{3}=|[A-Za-z0-9-_]{2}==)$");
+                //&& itemName.matches("^([A-Za-z0-9-_]{4})*([A-Za-z0-9-_]{4}|[A-Za-z0-9-_]{3}=|[A-Za-z0-9-_]{2}==)$")
+                && itemName.indexOf(' ') < 0;
     }