diff --git a/Assets/WorkSpace/LH/MQTTManager.cs b/Assets/WorkSpace/LH/MQTTManager.cs
index d3c628d5..fd711b1e 100644
--- a/Assets/WorkSpace/LH/MQTTManager.cs
+++ b/Assets/WorkSpace/LH/MQTTManager.cs
@@ -86,6 +86,16 @@ namespace Octopus.Simulator.Networks
 
         public void Connect(string clientName, string host, int port)
         {
+            if (client != null)
+            {
+                flag = true;
+                clientTable.Remove(clientName);
+                client.OnConnected -= ((client) => OnConnected(client, clientName));
+                client.OnStateChanged -= OnStateChange;
+                client.OnDisconnect -= OnDisconnected;
+                client.OnError -= OnError;
+            }
+
             if (string.Equals(protocol, "wss"))
             {
                 client = new MQTTClientBuilder()