diff --git a/logon_state_test.go b/logon_state_test.go
index 96afc2e90..ee47a2be6 100644
--- a/logon_state_test.go
+++ b/logon_state_test.go
@@ -333,7 +333,7 @@ func (s *LogonStateTestSuite) TestFixMsgInLogonSeqNumTooHigh() {
 	s.Require().Nil(err)
 	s.MessageType(string(msgTypeLogon), sentMessage)
 
-	s.session.sendQueued()
+	s.session.sendQueued(true)
 	s.MessageType(string(msgTypeResendRequest), s.MockApp.lastToAdmin)
 	s.FieldEquals(tagBeginSeqNo, 1, s.MockApp.lastToAdmin.Body)
 
@@ -373,7 +373,7 @@ func (s *LogonStateTestSuite) TestFixMsgInLogonSeqNumTooLow() {
 	s.Require().Nil(err)
 	s.MessageType(string(msgTypeLogout), sentMessage)
 
-	s.session.sendQueued()
+	s.session.sendQueued(true)
 	s.MessageType(string(msgTypeLogout), s.MockApp.lastToAdmin)
 	s.FieldEquals(tagText, "MsgSeqNum too low, expecting 2 but received 1", s.MockApp.lastToAdmin.Body)
 }
diff --git a/session.go b/session.go
index b359245e2..1bf60b122 100644
--- a/session.go
+++ b/session.go
@@ -235,12 +235,16 @@ func (s *session) queueForSend(msg *Message) error {
 
 	s.toSend = append(s.toSend, msgBytes)
 
+	s.notifyMessageOut()
+
+	return nil
+}
+
+func (s *session) notifyMessageOut() {
 	select {
 	case s.messageEvent <- true:
 	default:
 	}
-
-	return nil
 }
 
 // send will validate, persist, queue the message. If the session is logged on, send all messages in the queue.
@@ -261,7 +265,7 @@ func (s *session) sendInReplyTo(msg *Message, inReplyTo *Message) error {
 	}
 
 	s.toSend = append(s.toSend, msgBytes)
-	s.sendQueued()
+	s.sendQueued(true)
 
 	return nil
 }
@@ -290,7 +294,7 @@ func (s *session) dropAndSendInReplyTo(msg *Message, inReplyTo *Message) error {
 
 	s.dropQueued()
 	s.toSend = append(s.toSend, msgBytes)
-	s.sendQueued()
+	s.sendQueued(true)
 
 	return nil
 }
@@ -346,9 +350,13 @@ func (s *session) persist(seqNum int, msgBytes []byte) error {
 	return s.store.IncrNextSenderMsgSeqNum()
 }
 
-func (s *session) sendQueued() {
-	for _, msgBytes := range s.toSend {
-		s.sendBytes(msgBytes)
+func (s *session) sendQueued(blockUntilSent bool) {
+	for i, msgBytes := range s.toSend {
+		if !s.sendBytes(msgBytes, blockUntilSent) {
+			s.toSend = s.toSend[i:]
+			s.notifyMessageOut()
+			return
+		}
 	}
 
 	s.dropQueued()
@@ -363,18 +371,30 @@ func (s *session) EnqueueBytesAndSend(msg []byte) {
 	defer s.sendMutex.Unlock()
 
 	s.toSend = append(s.toSend, msg)
-	s.sendQueued()
+	s.sendQueued(true)
 }
 
-func (s *session) sendBytes(msg []byte) {
+func (s *session) sendBytes(msg []byte, blockUntilSent bool) bool {
 	if s.messageOut == nil {
 		s.log.OnEventf("Failed to send: disconnected")
-		return
+		return false
+	}
+
+	if blockUntilSent {
+		s.messageOut <- msg
+		s.log.OnOutgoing(msg)
+		s.stateTimer.Reset(s.HeartBtInt)
+		return true
 	}
 
-	s.log.OnOutgoing(msg)
-	s.messageOut <- msg
-	s.stateTimer.Reset(s.HeartBtInt)
+	select {
+	case s.messageOut <- msg:
+		s.log.OnOutgoing(msg)
+		s.stateTimer.Reset(s.HeartBtInt)
+		return true
+	default:
+		return false
+	}
 }
 
 func (s *session) doTargetTooHigh(reject targetTooHigh) (nextState resendState, err error) {
diff --git a/session_state.go b/session_state.go
index 230ac8613..527556209 100644
--- a/session_state.go
+++ b/session_state.go
@@ -105,7 +105,7 @@ func (sm *stateMachine) SendAppMessages(session *session) {
 	defer session.sendMutex.Unlock()
 
 	if session.IsLoggedOn() {
-		session.sendQueued()
+		session.sendQueued(false)
 	} else {
 		session.dropQueued()
 	}