diff --git a/src/node_rtmp_session.js b/src/node_rtmp_session.js
index 74cb068615cebb5854a111439ac5fde7e3ef944b..1a97d44d5258191e595ad28ab44efbb62d862447 100644
--- a/src/node_rtmp_session.js
+++ b/src/node_rtmp_session.js
@@ -203,11 +203,12 @@ class NodeRtmpSession {
     if (this.isStarting) {
       this.isStarting = false;
 
-      if (this.playStreamId > 0) {
+      // Don't rely on stream ids: a client can play/publish on stream id 0
+      if (this.isPlaying || this.isIdling) {
         this.onDeleteStream({ streamId: this.playStreamId });
       }
 
-      if (this.publishStreamId > 0) {
+      if (this.isPublishing) {
         this.onDeleteStream({ streamId: this.publishStreamId });
       }
 
@@ -1112,6 +1113,12 @@ class NodeRtmpSession {
     if (typeof invokeMessage.streamName !== 'string') {
       return;
     }
+    // Check before overwriting publish stream path/id, otherwise the current publisher can never be cleaned up
+    if (this.isPublishing) {
+      Logger.log(`[rtmp publish] NetConnection is publishing. id=${this.id} streamPath=${this.publishStreamPath} streamId=${this.publishStreamId}`);
+      this.sendStatusMessage(this.parserPacket.header.stream_id, 'error', 'NetStream.Publish.BadConnection', 'Connection already publishing');
+      return;
+    }
     this.publishStreamPath = '/' + this.appname + '/' + invokeMessage.streamName.split('?')[0];
     this.publishArgs = QueryString.parse(invokeMessage.streamName.split('?')[1]);
     this.publishStreamId = this.parserPacket.header.stream_id;
@@ -1133,9 +1140,6 @@ class NodeRtmpSession {
       this.reject();
       Logger.log(`[rtmp publish] Already has a stream. id=${this.id} streamPath=${this.publishStreamPath} streamId=${this.publishStreamId}`);
       this.sendStatusMessage(this.publishStreamId, 'error', 'NetStream.Publish.BadName', 'Stream already publishing');
-    } else if (this.isPublishing) {
-      Logger.log(`[rtmp publish] NetConnection is publishing. id=${this.id} streamPath=${this.publishStreamPath} streamId=${this.publishStreamId}`);
-      this.sendStatusMessage(this.publishStreamId, 'error', 'NetStream.Publish.BadConnection', 'Connection already publishing');
     } else {
       Logger.log(`[rtmp publish] New stream. id=${this.id} streamPath=${this.publishStreamPath} streamId=${this.publishStreamId}`);
       context.publishers.set(this.publishStreamPath, this.id);
@@ -1157,6 +1161,12 @@ class NodeRtmpSession {
     if (typeof invokeMessage.streamName !== 'string') {
       return;
     }
+    // Check before overwriting play stream path/id, otherwise the current player can never be cleaned up
+    if (this.isPlaying || this.isIdling) {
+      Logger.log(`[rtmp play] NetConnection is playing. id=${this.id} streamPath=${this.playStreamPath} streamId=${this.playStreamId}`);
+      this.sendStatusMessage(this.parserPacket.header.stream_id, 'error', 'NetStream.Play.BadConnection', 'Connection already playing');
+      return;
+    }
     this.playStreamPath = '/' + this.appname + '/' + invokeMessage.streamName.split('?')[0];
     this.playArgs = QueryString.parse(invokeMessage.streamName.split('?')[1]);
     this.playStreamId = this.parserPacket.header.stream_id;
@@ -1175,12 +1185,7 @@ class NodeRtmpSession {
       }
     }
 
-    if (this.isPlaying) {
-      Logger.log(`[rtmp play] NetConnection is playing. id=${this.id} streamPath=${this.playStreamPath}  streamId=${this.playStreamId} `);
-      this.sendStatusMessage(this.playStreamId, 'error', 'NetStream.Play.BadConnection', 'Connection already playing');
-    } else {
-      this.respondPlay();
-    }
+    this.respondPlay();
 
     if (context.publishers.has(this.playStreamPath)) {
       this.onStartPlay();
@@ -1194,6 +1199,9 @@ class NodeRtmpSession {
   onStartPlay() {
     let publisherId = context.publishers.get(this.playStreamPath);
     let publisher = context.sessions.get(publisherId);
+    if (!publisher) {
+      return;
+    }
     let players = publisher.players;
     players.add(this.id);
 
@@ -1305,7 +1313,7 @@ class NodeRtmpSession {
   }
 
   onDeleteStream(invokeMessage) {
-    if (invokeMessage.streamId == this.playStreamId) {
+    if (invokeMessage.streamId == this.playStreamId && (this.isPlaying || this.isIdling)) {
       if (this.isIdling) {
         context.idlePlayers.delete(this.id);
         this.isIdling = false;
@@ -1335,6 +1343,7 @@ class NodeRtmpSession {
 
         for (let playerId of this.players) {
           let playerSession = context.sessions.get(playerId);
+          if (!playerSession) continue;
           if (playerSession instanceof NodeRtmpSession) {
             playerSession.sendStatusMessage(playerSession.playStreamId, 'status', 'NetStream.Play.UnpublishNotify', 'stream is now unpublished.');
             playerSession.flush();
@@ -1346,6 +1355,7 @@ class NodeRtmpSession {
         //let the players to idlePlayers
         for (let playerId of this.players) {
           let playerSession = context.sessions.get(playerId);
+          if (!playerSession) continue;
           context.idlePlayers.add(playerId);
           playerSession.isPlaying = false;
           playerSession.isIdling = true;