diff --git a/src/neo/Network/P2P/MessageCommand.cs b/src/neo/Network/P2P/MessageCommand.cs
index ccddacfba2..771a98a459 100644
--- a/src/neo/Network/P2P/MessageCommand.cs
+++ b/src/neo/Network/P2P/MessageCommand.cs
@@ -33,6 +33,7 @@ public enum MessageCommand : byte
         GetData = 0x28,
         [ReflectionCache(typeof(GetBlockDataPayload))]
         GetBlockData = 0x29,
+        [ReflectionCache(typeof(InvPayload))]
         NotFound = 0x2a,
         [ReflectionCache(typeof(Transaction))]
         Transaction = 0x2b,
diff --git a/src/neo/Network/P2P/RemoteNode.ProtocolHandler.cs b/src/neo/Network/P2P/RemoteNode.ProtocolHandler.cs
index 91b3921326..2146501e85 100644
--- a/src/neo/Network/P2P/RemoteNode.ProtocolHandler.cs
+++ b/src/neo/Network/P2P/RemoteNode.ProtocolHandler.cs
@@ -217,8 +217,8 @@ private void OnGetBlockDataMessageReceived(GetBlockDataPayload payload)
         /// <param name="payload">The payload containing the requested information.</param>
         private void OnGetDataMessageReceived(InvPayload payload)
         {
-            UInt256[] hashes = payload.Hashes.Where(p => sentHashes.Add(p)).ToArray();
-            foreach (UInt256 hash in hashes)
+            var notFound = new List<UInt256>();
+            foreach (UInt256 hash in payload.Hashes.Where(p => sentHashes.Add(p)))
             {
                 switch (payload.Type)
                 {
@@ -226,6 +226,8 @@ private void OnGetDataMessageReceived(InvPayload payload)
                         Transaction tx = Blockchain.Singleton.GetTransaction(hash);
                         if (tx != null)
                             EnqueueMessage(Message.Create(MessageCommand.Transaction, tx));
+                        else
+                            notFound.Add(hash);
                         break;
                     case InventoryType.Block:
                         Block block = Blockchain.Singleton.GetBlock(hash);
@@ -241,6 +243,10 @@ private void OnGetDataMessageReceived(InvPayload payload)
                                 EnqueueMessage(Message.Create(MessageCommand.MerkleBlock, MerkleBlockPayload.Create(block, flags)));
                             }
                         }
+                        else
+                        {
+                            notFound.Add(hash);
+                        }
                         break;
                     case InventoryType.Consensus:
                         if (Blockchain.Singleton.ConsensusRelayCache.TryGet(hash, out IInventory inventoryConsensus))
@@ -248,6 +254,12 @@ private void OnGetDataMessageReceived(InvPayload payload)
                         break;
                 }
             }
+
+            if (notFound.Count > 0)
+            {
+                foreach (InvPayload entry in InvPayload.CreateGroup(payload.Type, notFound.ToArray()))
+                    EnqueueMessage(Message.Create(MessageCommand.NotFound, entry));
+            }
         }
 
         /// <summary>