diff --git a/pkg/mixer/mixer.go b/pkg/mixer/mixer.go
index 7d6ac47..e4dfa1c 100644
--- a/pkg/mixer/mixer.go
+++ b/pkg/mixer/mixer.go
@@ -157,12 +157,20 @@ func (m *Mixer) start() {
 }
 
 func (m *Mixer) Stop() {
+	m.mu.Lock()
+	defer m.mu.Unlock()
 	m.stopped.Break()
 }
 
 func (m *Mixer) NewInput() *Input {
+	if m == nil {
+		return nil
+	}
 	m.mu.Lock()
 	defer m.mu.Unlock()
+	if m.stopped.IsBroken() {
+		return nil
+	}
 
 	inp := &Input{
 		m:          m,
@@ -222,6 +230,9 @@ func (i *Input) SampleRate() int {
 }
 
 func (i *Input) Close() error {
+	if i == nil {
+		return nil
+	}
 	i.m.RemoveInput(i)
 	return nil
 }
diff --git a/pkg/sip/inbound.go b/pkg/sip/inbound.go
index 3926bb2..27dc180 100644
--- a/pkg/sip/inbound.go
+++ b/pkg/sip/inbound.go
@@ -838,6 +838,9 @@ func (c *inboundCall) joinRoom(ctx context.Context, rconf RoomConfig, status Cal
 
 func (c *inboundCall) playAudio(ctx context.Context, frames []media.PCM16Sample) {
 	t := c.lkRoom.NewTrack()
+	if t == nil {
+		return // closed
+	}
 	defer t.Close()
 
 	sampleRate := res.SampleRate
diff --git a/pkg/sip/room.go b/pkg/sip/room.go
index 32103cc..749552c 100644
--- a/pkg/sip/room.go
+++ b/pkg/sip/room.go
@@ -189,6 +189,9 @@ func (r *Room) Connect(conf *config.Config, rconf RoomConfig) error {
 
 				go func() {
 					mTrack := r.NewTrack()
+					if mTrack == nil {
+						return // closed
+					}
 					defer mTrack.Close()
 
 					odec, err := opus.Decode(mTrack, channels, log)
@@ -352,7 +355,6 @@ func (r *Room) CloseWithReason(reason livekit.DisconnectReason) error {
 	}
 	if r.mix != nil {
 		r.mix.Stop()
-		r.mix = nil
 	}
 	return err
 }
@@ -391,5 +393,8 @@ func (r *Room) SendData(data lksdk.DataPacket, opts ...lksdk.DataPublishOption)
 }
 
 func (r *Room) NewTrack() *mixer.Input {
+	if r == nil {
+		return nil
+	}
 	return r.mix.NewInput()
 }