Not very likely that it’s the speakers, but not impossible, either. But with two, it’s even more unlikely to be the speakers. 

In general, the most common reasons for disconnects are either wifi interference, or a duplicate IP address issues. There are others, but they are exceedingly rare. 

I am mildly concerned about your comment about standing next to your speaker being a consideration. The Sonos controller doesn’t connect from your phone directly to the speaker. Instead, the signal goes from your phone, to your router, and then from the router to the speaker. And any response follows the same path. 

You haven’t indicated what actions you’ve tried at the directions of the Sonos folks, so I’ll give some rather generic advice. 

First, of course, is to read the FAQ I linked above. Be aware that there is a very real possibility that the interference comes from outside your own network, and home. We all like to think we live in a bubble, but especially when talking about radio interference, it can come from both non network devices inside our homes, and signals from outside our home. 

Second, make sure that any Sonos  device is as least three feet (1 meter ) from your router. 

Third, check your router for firmware/software updates, and apply them. 

Fourth, try a simple network refresh, by unplugging all your Sonos devices from power, then reboot your router. When the router comes back up, go back and plug in your Sonos devices. My confidence on this is low, given how long you’ve been dealing with the issue, but it can’t hurt, at least. 

Sonos folks, with the data in the diagnostics that you submit, should be able, I think, to see why your phone or speakers are disconnecting from your router. Unfortunate, likely due to security and privacy laws, they don’t expose the contents of that data to anyone outside of Sonos.

I just want to say that I’ve had a very similar experience and it’s been on going for the best part of two years, I’ve been told by their top tier of technical support that I should expect this type of problem as I don’t live in a “pristine environment “

when it works it’s brilliant but sadly that is too infrequently to balance out the disappointment. 

This video is worth a watch, it covers some of the basics that’s if you haven’t seen it before:

https://youtu.be/3fQAAL5IwTE

Just curious as to what type of wireless setup you have and what channels and channel-widths for each band were recommended to you for your particular setup?

Thanks Ken. This is my problem, I’m not technically minded I went in a large department store and spent just shy of £2,000 on my set up, it’s sold as plug and play. If you look at Sonos’s own advertising literature it says they have the means to allow you to have a speaker in the cellar and another in the attic, the reality is so different. I live in a Victorian house over two floors but yet the system is sketchy at best. 
what I can tell you is that I have spent days talking to Sonos’s rather elusive tech support bods, I’ve tried everything they have suggested and they’ve thrown in the towel, apparently there is too much interference from my neighbours’ broadband etc. Which is odd because I live in a suburban area with detached houses. The term I used (pristine environment) is a direct quote from the senior tier of Sonos support, in fact his closing statement was “you can’t expect the system to be foolproof because you don’t live in a pristine environment”

my beef is this is sold as a consumer product but the reality is that it’s pot luck and the support is poor and getting worse. I object to be pushed into using a forum for support, Sonos isn’t a mom and pop organisation so why are WE allowing them to pass off their responsibilities? 
Great speakers, great sound, great looks but over engineered and not consumer friendly. 

It might be easier in your case ‘perhaps’, to find a friend, or a work colleague who has some basic knowledge of home networking and get them to help set things up for you.
 

It’s otherwise difficult to try to assist you, particularly if you are unable to describe your network setup, like channels, channel-widths etc. 
 

Sonos will work out the box, but it needs a stable wireless/wired home network connection to do that and it might be a case that you need to make your home network more robust ...I guess that requires a little bit of networking knowledge, which a friend/colleague may perhaps provide.

Thanks Ken. Sadly I can’t call on anyone with the relevant skills. That said I have exhausted Sonos’s tech support, looking at this forum I’m not alone and I maintain that so is are failing their clients by making this the go to solution. 
mill have to wait until apple decide to do this kind of system 

I may have found the solution to my issue. Before I had the same SSID for both the 2.4GHz and the 5GHz channels of my wi-fi router. Now I have renamed them so there is a separate/distinct name for each of these (for example mynet-2.4 and mynet-5 ). After making this change I reset the Sonos speakers to use the 2.4GHz SSID and then I connected to the same network on my phone.

So it seems that having both the phone and the Sonos on the same band/channel (what’s the correct term?) was the requirement I was violating before. Apparently there’s no way for Sonos to be available on both bands, so you have to choose which one you want t use for Sonos and then use that as well on the phone.

 @P1553d off  -- you’ve stated more eloquently than I could my frustrations around this. Sonos may be plug and play in limited cases (virgin/pristine/stable network), but even in my case where I live in a detached house not very near another and with a normal/basic wi-fi router setup I still have issues over 50% of the time and gave up using Sonos multiple times since it was so frustrating to have it fail to connect randomly/erratically. None of the tech support from Sonos has helped me resolve this issue, I stumbled on this solution myself. I’m a Data Engineer, not exactly inept with technology in general, and this was challenging for me and eventually took years to resolve (my Sonos speakers were expensive door stops for much of that time, it wasn’t worth the frustration). How are less technically savvy users faring?

These things are very hard to get right, or working at all, I get it. But it’s sold as way more “plug-and-play” than it really is, and it looks like Sonos’ (or at least @Ken_Griffiths) idea of plug and play is different from the commonly accepted meaning.

James Adams, bless your heart!

at last someone who ‘gets it’

sadly I’m not capable of doing what you suggest so I’ll bounce along with my love/hate relationship with Sonos (at least I feel there’s hope)

happy new year 

I just wanted to follow up to report that this is no longer an issue for me after changing phones. My previous phone was a Motorola MotoX and the current phone is a Samsung Galaxy S9.

So there may have been something amiss with just that phone, or with that make/model in general, I don’t know. However with the new phone the Sonos Android app has worked 100% of the time on both Wi-Fi bands (2.4 and 5).