diff --git a/src/Simplex/Messaging/Agent.hs b/src/Simplex/Messaging/Agent.hs
index 98eb84da1..1f3d7099e 100644
--- a/src/Simplex/Messaging/Agent.hs
+++ b/src/Simplex/Messaging/Agent.hs
@@ -1045,7 +1045,6 @@ runSmpQueueMsgDelivery c@AgentClient {subQ} cData@ConnData {connId, duplexHandsh
                   withStore' c $ \db -> do
                     setSndQueueStatus db sq Confirmed
                     when (isJust rq_) $ removeConfirmations db connId
-                  -- TODO possibly notification flag should be ON for one of the parties, to result in contact connected notification
                   unless (duplexHandshake == Just True) . void $ enqueueMessage c cData sq SMP.noMsgFlags HELLO
                 AM_CONN_INFO_REPLY -> pure ()
                 AM_REPLY_ -> pure ()
diff --git a/src/Simplex/Messaging/Agent/Client.hs b/src/Simplex/Messaging/Agent/Client.hs
index e47509be3..9a3642767 100644
--- a/src/Simplex/Messaging/Agent/Client.hs
+++ b/src/Simplex/Messaging/Agent/Client.hs
@@ -98,7 +98,7 @@ import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
 import Data.Either (isRight, partitionEithers)
 import Data.Functor (($>))
-import Data.List (partition, (\\))
+import Data.List (partition)
 import Data.List.NonEmpty (NonEmpty (..))
 import qualified Data.List.NonEmpty as L
 import Data.Map.Strict (Map)
@@ -303,12 +303,9 @@ getSMPServerClient c@AgentClient {active, smpClients, msgQ} srv = do
         removeClientAndSubs :: IO ([RcvQueue], [ConnId])
         removeClientAndSubs = atomically $ do
           TM.delete srv smpClients
-          qs <- RQ.getDelSrvQueues srv $ activeSubs c
+          (qs, conns) <- RQ.getDelSrvQueues srv $ activeSubs c
           mapM_ (`RQ.addQueue` pendingSubs c) qs
-          cs <- RQ.getConns (activeSubs c)
-          -- TODO deduplicate conns
-          let conns = map (connId :: RcvQueue -> ConnId) qs \\ S.toList cs
-          pure (qs, conns)
+          pure (qs, S.toList conns)
 
         serverDown :: ([RcvQueue], [ConnId]) -> IO ()
         serverDown (qs, conns) = whenM (readTVarIO active) $ do
@@ -345,8 +342,7 @@ getSMPServerClient c@AgentClient {active, smpClients, msgQ} srv = do
             unless connected . forM_ client_ $ \cl -> do
               incClientStat c cl "CONNECT" ""
               notifySub "" $ hostEvent CONNECT cl
-            -- TODO deduplicate okConns
-            let conns = okConns \\ S.toList cs
+            let conns = S.toList $ S.fromList okConns `S.difference` cs
             unless (null conns) $ notifySub "" $ UP srv conns
           let (tempErrs, finalErrs) = partition (temporaryAgentError . snd) errs
           liftIO $ mapM_ (\(connId, e) -> notifySub connId $ ERR e) finalErrs
@@ -647,8 +643,7 @@ temporaryOrHostError = \case
 subscribeQueues :: AgentMonad m => AgentClient -> SMPServer -> [RcvQueue] -> m (Maybe SMPClient, [(RcvQueue, Either AgentErrorType ())])
 subscribeQueues c srv qs = do
   (errs, qs_) <- partitionEithers <$> mapM checkQueue qs
-  forM_ qs_ $ \rq@RcvQueue {connId, server = _server} -> atomically $ do
-    -- TODO check server is correct
+  forM_ qs_ $ \rq@RcvQueue {connId} -> atomically $ do
     modifyTVar (subscrConns c) $ S.insert connId
     RQ.addQueue rq $ pendingSubs c
   case L.nonEmpty qs_ of
@@ -667,9 +662,11 @@ subscribeQueues c srv qs = do
             pure $ map (second . first $ protocolClientError SMP $ clientServer smp) rs
     _ -> pure (Nothing, errs)
   where
-    checkQueue rq@RcvQueue {rcvId, server} = do
-      prohibited <- atomically . TM.member (server, rcvId) $ getMsgLocks c
-      pure $ if prohibited || srv /= server then Left (rq, Left $ CMD PROHIBITED) else Right rq
+    checkQueue rq@RcvQueue {rcvId, server}
+      | server == srv = do
+        prohibited <- atomically . TM.member (server, rcvId) $ getMsgLocks c
+        pure $ if prohibited || srv /= server then Left (rq, Left $ CMD PROHIBITED) else Right rq
+      | otherwise = pure $ Left (rq, Left $ INTERNAL "queue server does not match parameter")
     queueCreds RcvQueue {rcvPrivateKey, rcvId} = (rcvPrivateKey, rcvId)
 
 addSubscription :: MonadIO m => AgentClient -> RcvQueue -> m ()
diff --git a/src/Simplex/Messaging/Agent/TRcvQueues.hs b/src/Simplex/Messaging/Agent/TRcvQueues.hs
index bed4138a2..9ace32db7 100644
--- a/src/Simplex/Messaging/Agent/TRcvQueues.hs
+++ b/src/Simplex/Messaging/Agent/TRcvQueues.hs
@@ -40,9 +40,9 @@ getSrvQueues srv (TRcvQueues qs) = M.foldl' addQ [] <$> readTVar qs
   where
     addQ qs' rq@RcvQueue {server} = if srv == server then rq : qs' else qs'
 
-getDelSrvQueues :: SMPServer -> TRcvQueues -> STM [RcvQueue]
-getDelSrvQueues srv (TRcvQueues qs) = stateTVar qs $ M.foldl' addQ ([], M.empty)
+getDelSrvQueues :: SMPServer -> TRcvQueues -> STM ([RcvQueue], Set ConnId)
+getDelSrvQueues srv (TRcvQueues qs) = stateTVar qs $ M.foldl' addQ (([], S.empty), M.empty)
   where
-    addQ (removed, qs') rq@RcvQueue {server, rcvId}
-      | srv == server = (rq : removed, qs')
+    addQ (removed@(remQs, remConns), qs') rq@RcvQueue {connId, server, rcvId}
+      | srv == server = ((rq : remQs, S.insert connId remConns), qs')
       | otherwise = (removed, M.insert (server, rcvId) rq qs')
diff --git a/src/Simplex/Messaging/Protocol.hs b/src/Simplex/Messaging/Protocol.hs
index 645a26e3a..0263e374e 100644
--- a/src/Simplex/Messaging/Protocol.hs
+++ b/src/Simplex/Messaging/Protocol.hs
@@ -1160,26 +1160,33 @@ instance Encoding CommandError where
       _ -> fail "bad command error type"
 
 -- | Send signed SMP transmission to TCP transport.
-tPut :: Transport c => THandle c -> NonEmpty SentRawTransmission -> IO (NonEmpty (Either TransportError ()))
+tPut :: Transport c => THandle c -> NonEmpty SentRawTransmission -> IO [Either TransportError ()]
 tPut th trs
   | batch th = tPutBatch [] $ L.map tEncode trs
-  | otherwise = forM trs $ tPutBlock th . tEncode
+  | otherwise = forM (L.toList trs) $ tPutLog . tEncode
   where
-    tPutBatch :: [Either TransportError ()] -> NonEmpty ByteString -> IO (NonEmpty (Either TransportError ()))
+    tPutBatch :: [Either TransportError ()] -> NonEmpty ByteString -> IO [Either TransportError ()]
     tPutBatch rs ts = do
       let (n, s, ts_) = encodeBatch 0 "" ts
-      r <- if n == 0 then pure [Left TELargeMsg] else replicate n <$> tPutBlock th (lenEncode n `B.cons` s)
+      r <- if n == 0 then largeMsg else replicate n <$> tPutLog (lenEncode n `B.cons` s)
       let rs' = rs <> r
       case ts_ of
         Just ts' -> tPutBatch rs' ts'
-        _ -> pure $ L.fromList rs'
+        _ -> pure rs'
+    largeMsg = putStrLn "tPut error: large message" >> pure [Left TELargeMsg]
+    tPutLog s = do
+      r <- tPutBlock th s
+      case r of
+        Left e -> putStrLn ("tPut error: " <> show e)
+        _ -> pure ()
+      pure r
     encodeBatch :: Int -> ByteString -> NonEmpty ByteString -> (Int, ByteString, Maybe (NonEmpty ByteString))
     encodeBatch n s ts@(t :| ts_)
       | n == 255 = (n, s, Just ts)
       | otherwise =
         let s' = s <> smpEncode (Large t)
             n' = n + 1
-         in if B.length s' > blockSize th - 1
+         in if B.length s' > blockSize th - 1 -- one byte is reserved for the number of messages in the batch
               then (n,s,) $ if n == 0 then L.nonEmpty ts_ else Just ts
               else case L.nonEmpty ts_ of
                 Just ts' -> encodeBatch n' s' ts'
diff --git a/src/Simplex/Messaging/Server.hs b/src/Simplex/Messaging/Server.hs
index 1bf3d46df..52c3558ed 100644
--- a/src/Simplex/Messaging/Server.hs
+++ b/src/Simplex/Messaging/Server.hs
@@ -256,7 +256,6 @@ receive th Client {rcvQ, sndQ, activeAt} = forever $ do
 send :: Transport c => THandle c -> Client -> IO ()
 send h@THandle {thVersion = v} Client {sndQ, sessionId, activeAt} = forever $ do
   ts <- atomically $ L.sortWith tOrder <$> readTBQueue sndQ
-  -- TODO the line below can return Lefts, but we ignore it and do not disconnect the client
   void . liftIO . tPut h $ L.map ((Nothing,) . encodeTransmission v sessionId) ts
   atomically . writeTVar activeAt =<< liftIO getSystemTime
   where