diff --git a/p2p/peer.py b/p2p/peer.py
index eda46fa605..fde49b35de 100644
--- a/p2p/peer.py
+++ b/p2p/peer.py
@@ -383,14 +383,19 @@ def handle_p2p_msg(self, cmd: protocol.Command, msg: protocol._DecodedMsgType) -
             raise UnexpectedMessage("Unexpected msg: {} ({})".format(cmd, msg))
 
     def handle_sub_proto_msg(self, cmd: protocol.Command, msg: protocol._DecodedMsgType) -> None:
+        cmd_type = type(cmd)
+
         if self._subscribers:
-            for subscriber in self._subscribers:
-                subscriber.add_msg((self, cmd, msg))
+            was_added = tuple(subscriber.add_msg((self, cmd, msg)) for subscriber in self._subscribers)
+            if not any(was_added):
+                self.logger.warn(
+                    "Peer %s has no subscribers for msg type %s",
+                    self,
+                    cmd_type.__name__,
+                )
         else:
             self.logger.warn("Peer %s has no subscribers, discarding %s msg", self, cmd)
 
-        cmd_type = type(cmd)
-
         if cmd_type in self.pending_requests:
             request, future = self.pending_requests[cmd_type]
             try:
@@ -607,18 +612,20 @@ def add_msg(self, msg: 'PEER_MSG_TYPE') -> None:
                     "subscriptions: %s",
                     cmd, peer, self.subscription_msg_types,
                 )
-            return
+            return False
 
         try:
             if hasattr(self, 'logger'):
                 self.logger.trace(  # type: ignore
                     "Adding %s msg from %s to queue; queue_size=%d", cmd, peer, self.queue_size)
             self.msg_queue.put_nowait(msg)
+            return True
         except asyncio.queues.QueueFull:
             if hasattr(self, 'logger'):
                 self.logger.warn(  # type: ignore
                     "%s msg queue is full; discarding %s msg from %s",
                     self.__class__.__name__, cmd, peer)
+            return False
 
     @contextlib.contextmanager
     def subscribe(self, peer_pool: 'PeerPool') -> Iterator[None]: