The new Era I can’t help with but you could try submitting a diagnostic to Sonos next time you have issues and request they look at it. They can often spot issues from the internal data that a normal user has no access to.

For the cost of an Ethernet cable, I’d try just one and see if that makes the difference. But the Era is wifi or Ethernet only - they do not support SonosNet like older speakers so it does depend on other factors too. 

I see that this is the third thread you’ve started relating to your issues. Have you set fixed ip addresses for your speakers, to see if that helps? What else did support suggest when you contacted them previously? Is there a lot of wifi interference? 

Hi Nik, thanks for the response. I have indeed set fixed ip addressed for the speakers. My issues are strange. For a time, my android phone (Xperia 1) was not able to reliably detect the speaker pair but my laptop and other phones were able to see it. So, I figured it was an issue with my phone. But beyond that, when I play Bluetooth on the pair, it consistently cuts out audio on one of the speakers. I also use double twist app which can airplay to the speakers but the audio still cuts out using them. 

At this point I called Sonos support and had them try to help me. The only thing they were able to tell me was that one of the speakers was getting interference. They told me to check the support articles on that stuff which as you can imagine I've already read a dozen times. I asked them to send me a replacement for the one that was cutting out and they did - hoping it was a faulty speaker. Unfortunately I'm still having connectivity issues and it's quite unlikely that the speakers are faulty at this point. 

I'm at my wits end because I cannot figure out what could be causing interference. The app says they have good to excellent connection to the network... And the only other wifi devices even remotely nearby are my front and back door nest doorbells.

So, I've given up on trying to solve the issue any way other than by running an ethernet cable. My problem is this cable would need to be routed from my 2nd floor where the router is, through an exterior wall (that's going to be fun) down to the first floor where the speakers are.  

For aesthetic reasons I'd prefer to only need to hardwire the speaker that will be located near the ethernet jack and not have to have another cable run along the floor to the other pair. 

Although it’s not recommended by Sonos, you could maybe try Ethernet over powerline  https://support.sonos.com/en-us/article/recommended-settings-for-using-sonos-with-ethernet-networks  That might make cabling easier, if it works for you  

Is your wifi set to Auto channel, or fixed on one of the channels 1, 6 or 11? 

I've set it to a fixed channel. And I've tried changing it between those 3, doesn't seem to have made a difference. What I really want to know is how the speakers communicate when paired.

Does 1 speaker receive the audio information and then passes it wirelessly to the other one? If so, I get the feeling that hardwiring both of them may not solve one of the primary interference issues that I'm having.

EOP is my last choice, but sometimes it’s the miracle cure. EOP works best when outlets are wired to the same column in the same electrical panel. Heavy duty surge suppressors using the same outlet as EOP usually cause trouble for EOP.

I’m having similar issues.  I have created a stereo pair and connecting to Right Speaker using Line-In from my PC.  When it works it works well but I get I frequent disconnects from Right Speaker which results in no audio from eitrher speaker.  I have to use the app to reconnect Right Speaker which takes forever.  What I’ve found is if I exit discovery step the Right Speaker starts working again.  

I’ve had Sonos for years and have never any issues.  None.  Until now.  I bought a Boost to rule out Wifi issues but get the same problem so have I’ve just ordered 2 Sonos Combo Adapters so hopefully being wired via ethernet might fix the problem.

Just more money spent on something that should just work.