diff --git a/src/Simplex/Messaging/Server/QueueStore/STM.hs b/src/Simplex/Messaging/Server/QueueStore/STM.hs
index 00e87d520..101c26251 100644
--- a/src/Simplex/Messaging/Server/QueueStore/STM.hs
+++ b/src/Simplex/Messaging/Server/QueueStore/STM.hs
@@ -62,15 +62,14 @@ instance MonadQueueStore QueueStore STM where
         _ -> writeTVar qVar q {senderKey = Just sKey} $> Just q
 
   addQueueNotifier :: QueueStore -> RecipientId -> NtfCreds -> STM (Either ErrorType QueueRec)
-  addQueueNotifier QueueStore {queues, notifiers} rId ntfCreds@NtfCreds {notifierId} = do
-    ifM (TM.member notifierId notifiers) (pure $ Left DUPLICATE_) $
-      withQueue rId queues $ \qVar ->
-        readTVar qVar >>= \q -> case notifier q of
-          Just _ -> pure Nothing
-          _ -> do
-            writeTVar qVar q {notifier = Just ntfCreds}
-            TM.insert notifierId rId notifiers
-            pure $ Just q
+  addQueueNotifier QueueStore {queues, notifiers} rId ntfCreds@NtfCreds {notifierId = nId} = do
+    ifM (TM.member nId notifiers) (pure $ Left DUPLICATE_) $
+      withQueue rId queues $ \qVar -> do
+        q <- readTVar qVar
+        forM_ (notifier q) $ (`TM.delete` notifiers) . notifierId
+        writeTVar qVar q {notifier = Just ntfCreds}
+        TM.insert nId rId notifiers
+        pure $ Just q
 
   suspendQueue :: QueueStore -> RecipientId -> STM (Either ErrorType ())
   suspendQueue QueueStore {queues} rId =
diff --git a/tests/ServerTests.hs b/tests/ServerTests.hs
index 591f4c085..72d87fb28 100644
--- a/tests/ServerTests.hs
+++ b/tests/ServerTests.hs
@@ -612,7 +612,9 @@ testMessageNotifications (ATransport t) =
       (sId, rId, rKey, dhShared) <- createAndSecureQueue rh sPub
       let dec nonce = C.cbDecrypt dhShared (C.cbNonce nonce)
       (rcvNtfPubDhKey, _) <- C.generateKeyPair'
-      Resp "1" _ (NID nId _) <- signSendRecv rh rKey ("1", rId, NKEY nPub rcvNtfPubDhKey)
+      Resp "1" _ (NID nId' _) <- signSendRecv rh rKey ("1", rId, NKEY nPub rcvNtfPubDhKey)
+      Resp "1a" _ (NID nId _) <- signSendRecv rh rKey ("1a", rId, NKEY nPub rcvNtfPubDhKey)
+      nId' `shouldNotBe` nId
       Resp "2" _ OK <- signSendRecv nh1 nKey ("2", nId, NSUB)
       Resp "3" _ OK <- signSendRecv sh sKey ("3", sId, _SEND' "hello")
       Resp "" _ (MSG mId1 _ _ msg1) <- tGet rh