diff --git a/server/src/main/java/org/elasticsearch/transport/RemoteClusterCredentialsManager.java b/server/src/main/java/org/elasticsearch/transport/RemoteClusterCredentialsManager.java
index bc2e3ade7440..7a6df38addba 100644
--- a/server/src/main/java/org/elasticsearch/transport/RemoteClusterCredentialsManager.java
+++ b/server/src/main/java/org/elasticsearch/transport/RemoteClusterCredentialsManager.java
@@ -19,7 +19,6 @@
 import java.util.Collections;
 import java.util.Map;
 import java.util.Set;
-import java.util.TreeSet;
 
 import static org.elasticsearch.transport.RemoteClusterService.REMOTE_CLUSTER_CREDENTIALS;
 
@@ -37,7 +36,7 @@ public final synchronized UpdateRemoteClusterCredentialsResult updateClusterCred
         final Map<String, SecureString> newClusterCredentials = REMOTE_CLUSTER_CREDENTIALS.getAsMap(settings);
         if (clusterCredentials.isEmpty()) {
             setClusterCredentialsAndLog(newClusterCredentials);
-            return new UpdateRemoteClusterCredentialsResult(new TreeSet<>(newClusterCredentials.keySet()), Collections.emptySortedSet());
+            return new UpdateRemoteClusterCredentialsResult(Set.copyOf(newClusterCredentials.keySet()), Collections.emptySet());
         }
 
         final Set<String> addedClusterAliases = Sets.difference(newClusterCredentials.keySet(), clusterCredentials.keySet());