One of my Sonos speakers is constantly disconnecting

I'm going to hazard a guess that you're experiencing a duplicate IP address issue. Unless you rebooted the router while the two Sonos were unplugged, that would be a plausible, although slightly remote issue.

First step would be to do as I suggested. Unplug both speakers from power. Reboot the router. Then plug the speakers back in to power. This will force a refresh of both the DHCP table in the router, and force the speakers to request new IP addresses, rather than just trying to reconnect to the previous IP address.

If this "resolves" the issue, I'd recommend that you look in to the process of setting up reserved IP addresses in your router's manual. If the router has lost where it is in the automatic process of handing out IP addresses once, it's likely it might happen again....although I'll admit I have no idea what causes this error to occur. Possibly power surges, or just bad code, no idea.

However, this is a shot in the dark. The symptoms could be from something else. The next time you notice it, if the above doesn't work, I would recommend that you submit a system diagnostic within 10 minutes of recreating this issue, and either post the number here, or contact Sonos to discuss it. I tend to suggest the phone folks, they have more tools available, but are only available during business hours. Both the Twitter and Facebook support folks are available 24/7.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

Thanks for your reply . . . I'll try your suggestion and see what happens.

I don't know much about IP addresses. I have AT&T internet and it appears that I would need to pay $16 per month for 5 static IP addresses. I checked with Spectrum and I was told that they do not offer static IP addresses for residential customers. Is there anyway to avoid paying a monthly fee to have the ability to assign static IP addresses to these speakers?

And, in all honesty, it's entirely possible that my assumption is incorrect, and there's some other issue going on. :)

If my previous suggestion doesn't pan out, I would recommend that you submit a system diagnostic within 10 minutes of recreating this issue, and either post the number here, or contact Sonos to discuss it. I tend to suggest the phone folks, they have more tools available, but are only available during business hours. Both the Twitter and Facebook support folks are available 24/7.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

We are not talking about static tcp/ip addresses here, so don’t stress on that area.
If you followed setup instructions and you’re on dhcp, mist probable you’re not getting duplicate tcp/ip addresses.
But if you’re connecting via WiFi, that could be the problem as you’ve probably stretched your Wi-Fi coverage too far and or your router can’t handle the traffic, hence the reboots.
For a test run a 25-50’ cat 6 cable to each, if you don’t drop it’s a WiFi issue. If you still drop it’s a router issue, especially since you’re using an att built in combo router. Gistek.us Networks

I've spent a lot of time lately browsing the Sonos forums. I'm surprised how often the idea of duplicate IP addresses crops up. And how often I've seen DHCP address reservations being recommended. Is there something about Sonos that I'm missing? Or is it something about the Sonos community?

On your average home network, it's hard to get IP address conflicts. And even harder to get sporadic IP address conflicts. A dodgy router with buggy DHCP code? Just about every home router in the universe is linux based (as is sonos) and manufacturers have no reason to tamper with something as basic as DHCP code. If duplicate IP addresses really are as common as the Sonos community seems to think, they should be equally common in other places, such as router manufacturers' forums. They aren't.

Of course, most things can be screwed up if you're not sure what you're doing and your home network is no exception. IP address conflicts, when they do happen, are more likely to be caused by dodgy setups rather than by dodgy routers. Two classics are static IP addresses (often recommended for printers to apple users - but did you remember to do the necessary on your router?) and secondary wireless access points (did you disable their DHCP server if they have one?).

Back to the problem at hand... Unless you've done something strange, I wouldn't worry about IP addresses. I'll second Gistek's advice, adding following observation: do the dropouts happen when playing stored music? If you're playing internet radio or a streaming service, you can't tell whether or not the problem is in your network. The Sonos support people might be able to tell though.

I've spent a lot of time lately browsing the Sonos forums. I'm surprised how often the idea of duplicate IP addresses crops up. And how often I've seen DHCP address reservations being recommended. Is there something about Sonos that I'm missing? Or is it something about the Sonos community?
The first thing to note is that it's rare for Sonos users to have to deal with this; the vast, vast majority of users never come near this forum, and never need troubleshooting advice.

The most common cause for a duplicate IP issue is a router that's restarted for whatever reason, which usually flushes its reservation table. This can cause temporary issues until leases expire and all devices have requested IPs. Sonos devices and controllers can be badly affected by the presence of duplicate addresses because there is necessarily significant inter-device communication.

I called Sonos support and the technician had me re-establish the connection to the router and the wireless network. Two days later the opposite speaker dropped out. I submitted a diagnostic immediately after but have not yet been able to call back to see if Sonos will be able to nail down the cause with my diagnostic number. After the speaker dropped out, I connected both speakers to the router with ethernet cable to see what would happen. It's been a few days and no drop outs yet. Yes, there are a lot of posts regarding IP address conflicts . . . I do find it interesting that I have never had a problem with either of my Echos dropping out . . . only problems with the Sonos speakers.

. I do find it interesting that I have never had a problem with either of my Echos dropping out . . . only problems with the Sonos speakers.
I’ve had frequent disconnection problems with one of my Echo speakers, but pretty much no issues with my Sonos devices. Just another datapoint.