diff --git a/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/fastfail/ValidRcptHandler.java b/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/fastfail/ValidRcptHandler.java
index f435f305715..ca31b879881 100644
--- a/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/fastfail/ValidRcptHandler.java
+++ b/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/fastfail/ValidRcptHandler.java
@@ -18,13 +18,14 @@
  ****************************************************************/
 package org.apache.james.smtpserver.fastfail;
 
+import java.util.EnumSet;
+
 import jakarta.inject.Inject;
 
 import org.apache.commons.configuration2.Configuration;
 import org.apache.commons.configuration2.ex.ConfigurationException;
 import org.apache.james.core.Domain;
 import org.apache.james.core.MailAddress;
-import org.apache.james.core.Username;
 import org.apache.james.domainlist.api.DomainList;
 import org.apache.james.domainlist.api.DomainListException;
 import org.apache.james.protocols.api.handler.ProtocolHandler;
@@ -33,7 +34,7 @@
 import org.apache.james.rrt.api.RecipientRewriteTable;
 import org.apache.james.rrt.api.RecipientRewriteTable.ErrorMappingException;
 import org.apache.james.rrt.api.RecipientRewriteTableException;
-import org.apache.james.rrt.lib.Mappings;
+import org.apache.james.rrt.lib.Mapping;
 import org.apache.james.user.api.UsersRepository;
 import org.apache.james.user.api.UsersRepositoryException;
 import org.slf4j.Logger;
@@ -64,28 +65,44 @@ public void setSupportsRecipientRewriteTable(boolean supportsRecipientRewriteTab
 
     @Override
     protected boolean isValidRecipient(SMTPSession session, MailAddress recipient) throws UsersRepositoryException, RecipientRewriteTableException {
-        Username username = users.getUsername(recipient);
-
-        if (users.contains(username)) {
+        // Check existence of mailbox early to use RRT less often.
+        if (mailboxExists(recipient)) {
             return true;
-        } else {
-            return supportsRecipientRewriteTable && isRedirected(recipient, username.asString());
         }
+
+        // Check whether there is at least one valid mailbox after
+        // resolving the recipient using the RRT.
+        return isResolvableToAtLeastOneMailbox(recipient);
+    }
+
+    protected boolean mailboxExists(MailAddress recipient) throws UsersRepositoryException {
+        return users.contains(users.getUsername(recipient));
     }
 
-    private boolean isRedirected(MailAddress recipient, String username) throws RecipientRewriteTableException {
-        LOGGER.debug("Unknown user {} check if it's an alias", username);
+    private boolean isResolvableToAtLeastOneMailbox(MailAddress recipient) throws RecipientRewriteTableException {
+        if (!supportsRecipientRewriteTable) {
+            return false;
+        }
+        LOGGER.debug("Unknown recipient {}, resolving it via RRT", recipient);
 
         try {
-            Mappings targetString = recipientRewriteTable.getResolvedMappings(recipient.getLocalPart(), recipient.getDomain());
-
-            if (!targetString.isEmpty()) {
-                return true;
-            }
+            return recipientRewriteTable
+                // Error mappings are only used to forbid sending from the source address and can be ignored here.
+                .getResolvedMappings(recipient.getLocalPart(), recipient.getDomain(), EnumSet.complementOf(EnumSet.of(Mapping.Type.Error)))
+                .asStream()
+                .flatMap(mapping -> mapping.asMailAddress().stream())
+                .anyMatch(address -> {
+                    try {
+                        return mailboxExists(address);
+                    } catch (UsersRepositoryException e) {
+                        return false;
+                    }
+                });
         } catch (ErrorMappingException e) {
-            return true;
+            // As we filter the mappings above, this case should never happen.
+            LOGGER.error("Unexpexted mapping of type Error: ", e);
+            return false;
         }
-        return false;
     }
 
     @Override