I still see this issue aswell. I’ve cancelled my plex-pass as it has never really worked for me through the Sonos service, yet the Plex App works fine - remote access is fine too. 

In regards to your comment “The issue can be fixed by setting ‘Network > Secure connections’ to ‘Disabled’ on the Plex Server. It then works perfectly” - that doesn’t work for me either, but have you noticed that further down the network settings page, there is an option to “List networks and IP addresses allowed without auth” - you could try adding your local subnet in this format: 192.168.1.1/255.255.255.0 (just as an example - replace with your own subnet) and leave your ‘secure connections’ to the default ‘preferred’ option… whilst it doesn’t work for me, it might just work for you, perhaps?

I’ve given up trying to get it to work with the two Plex servers I have here on Netgear NAS boxes.

Are you having trouble accessing a local Plex server (same local network) or a remote one? I’m not seeing any issues with local access.

Sounds like it might be a different problem in your case.

Entering the private subnet of the remote network from which I’m trying to access the Plex server isn’t going to work, but I will try entering the public IP, as an experiment. The trouble with that is that it’s dynamic, however.

Fundamentally, something broke a few months ago, because it used to work without any problems and was a very good solution to sharing a large media library between Sonos systems in two different properties. I assumed that the issue would be noticed quickly and resolved, but no such luck.

Might be something as simple as a certificate expiry.

I can access my server(s) using the Plex App only both locally and remotely. My plex-pass is still valid until January 2022, but I’ve cancelled its renewal. I have forwarded the usual 32400 TCP port, or as an alternative have manually set my own port forwarding - with no joy. Even tried automatic port selection via UPnP.
 

Even tried forwarding all these ports to the NAS IP address (in my case there are two available Plex servers (192.168.7.120 and 192.168.7.220).. I tend to mainly use the latter.

• TCP port 32400 for the Plex Media Server
• UDP port 1900 for the Plex DLNA Server
• TCP port 3005 for Plex Companion
• UDP port 5353 for network discovery
• TCP port 8324 for Roku via Plex Companion
• UDP port 32410, 32412, 32413, 32414 for network discovery
• TCP port 32469 for the Plex DLNA Server

So all works fine with the Plex native App - the Plex service built-in to the Sonos App sees the server plex folders and the tracks and Artwork it even loads the tracks into the room queue, but then I get the message that the connection was lost. I can goto the same tracks on the Plex App and they work no problem and can even use the ‘connect’ sharing (API option) to play the track from the Plex App to the same Sonos speaker and that works fine too.

The tracks are part of a local shared library on the NAS and I can play them, no problem via the library shared folders in the Sonos App (SMB protocol).

Just the Plex service built into Sonos doesn’t seem to want to work for me. That’s using the iPad/iPhone S2 controller App. I’ve even gone to the lengths of factory resetting one of my NAS boxes and reinstalling all.. I’ve not yet found the answer to this one.

Yikes. Merrily forwarding inbound traffic on known ports is not a great idea. 

I’d assumed that Plex remote access normally used a NAT traversal technique. 

I didn’t say I had left them open - I was just mentioning the fact I had gone to those lengths.

@ratty, those are all the Ports that are apparently involved with the Plex service - the only one actually required for remote access is TCP port 32400 which most map to a different (random port) set manually in the Plex server software, or it can be done automatically using UPnP - I tend to go for the manual mapping option personally speaking. I also don’t leave the port open when the plex service is switched off.

Just for clarity … in my case:

My Plex server runs as a container under Docker on a Raspberry Pi. I have port 32400 (only) port-forwarded to the Raspberry Pi host, with the container configured to use ‘host’ networking.

Plex server software and Sonos firmware are the latest versions.

• All Plex apps (web, iOS, macOS) work fine, from any network, locally or remotely,
• Sonos/Plex integration works fine on the local network, with both S1 and S2 systems.
• Sonos/Plex integration works for search, but not playback, from a remote network. Only S1 tested. I used this successfully for ~1 year before it stopped working.

So, I don't think there’s a fundamental configuration error for either local or remote access. It’s just that Sonos has problems with the remote access scenario, and this appears to be security related.

I’ve got both S1/S2 systems here with the Plex service installed on both and the attached image shows a room queue (Hallway Play:1) from the S1 App. Plex happily populates the queue with all the tracks and Artwork, but nothing wants to play - I’ve not found the answer, despite quite some effort of searching for a solution - it is likely my WiFi/Network setup, I guess, but Plex is the only thing that doesn’t work, everything else works, including the same library shared over SMB, as part of the Sonos App, or it all works via the Plex App too, so it has me stumped.

It might be a security issue that’s staring me in the face, but perhaps I just can’t see it for looking.

So, this still doesn’t work.

Apparently no-one at Sonos or at Plex cares that their service integration has been non-functional for months.

I can confirm this with exactly the same result, but a little different setup. While using the native Plex Apps the playback works fine but as soon as i switch to the Sonos App, things don´t work anymore.

First i thought it must be something with my network setup (plex is behind a reverse proxy), but now i think it must be something with sonos app and the handling of the internal IPs/Ports or the DNS inside (or outside) of the App. It is strange, that the Sonos speakes do not even try to resolve my plex domain (or any others by the way).

So if i use the Sonos App, the Speaker tries to connect to my Plex Server. If i use the Plex native Apps it automatically connects to the Server and is streaming the Media directly from the Server. 

Monitoring the Network Connections Out of the Sonos Speaker and into my Plexserver while keeping an eye on the Plex Logs i can see that the requests are incoming from an external IP (not directly form the Sonos speaker) and they always get an Error 

pTranscode] Streaming Resource: Bandwidth exceeded: 2147483647 kbps > 40000 kbps

: while writing this i tried to disable bandwith limiting on the Plexserver (under remote access) and now it works….argh maybe this also temporary helps you but i think it is still thats needs to be resolved.

Sonos still does not work with remote Plex servers after the recent update (to S1 v11.3 in my case).

Could someone from Sonos please confirm that this defect has been reported to engineering?

Thanks.

Thanks for the suggestion, but I don’t have this option. Perhaps it’s a Plex Pass feature. As noted above, the errors I’m seeing appear to be security related.

I have issue with Plex on Sonos too and from my own research, it ‘appears’ it’s because the router needs to support NAT Loopback for it to work with plex pass. Unfortunately the router I’m using doesn’t have that feature although it was mentioned a year ago on their forum that they may change their firmware. They haven’t at the moment, so I’ve cancelled my plex pass for now and will just wait to see of this ever gets resolved.

It’s a pity that Plex can’t come up with a better way to resolve this as I’m happy to pay the Plex Pass subscription, but it’s no good to me if it doesn’t work through the Sonos App - it still works mind through the Plex ‘Native’ App.

Just to be clear, this not the issue I’m seeing. Access to a local Plex server from Sonos works fine, and I’m aware of the NAT loopback requirement.

The defective behaviour is with remote Plex server playback from Sonos.

Ah I see, in my case it’s local playback I can’t get to work.‍♂️

Just thought I’d add something here as I’ve just run into this problem.

Symptoms - I added Plex to Sonos, was able to browse content no problem but got an error “unable to connect to Plex” every time I tried to play a track.

My setup - Plex server running in docker container. NAT port forward on router allowing remote access.

Solution - I changed the port forward rule on my router to both LAN and WAN source not just WAN (see comments on NAT loopback above). Playback now working fine. I’m using OPNsense though and I don’t think that option is going to exist on most SOHO routers unfortunately, so unless you’re using opnsense / pfsense / openwrt it’s likely not possible.

Basically it looks like the Sonos Deezer integration is talking with the external (WAN) IP rather than local address when playing music.

I’ve now sorted my Plex service within the Sonos App too.. I had issues with NAT loopback and the router I was using, but the manufacturer ‘Plume’ (helpful support) has sorted it with a firmware update and so all works great. Love the Plex service too.

Deezer?! 

After messing around with router setting, enabling “ping from wan” solved it.