Hi.  Can I just check - is this your only Sonos device or do you have others?

I actually just learned from support that mobile broadband networks are not supported and you need to use the device only with wired internet connection. The bandwithd is not an issue since I manage to use my online meeting tools with video and audio successfully but for Sonos that is not an suitable solution

You mentioned that you tried different WiFi routers, were they each running mobile networks?

What make/models and mobile networks were they? … it would perhaps be helpful to know a little more detail, just in case others come across the same issue. Was it the mobile network provider blocking the use of Sonos, or the router hardware?

Hi

it is Sonos S1 and S2 system requirements which can be found on the support page

https://support.sonos.com/en/article/sonos-system-requirements

it clearly says that you need wired internet connection and no LTEs and such are supported.

All my network routers were behind the same LTE modem, it is not blocked by carrier and the bandwith should not be an issue (+100 Mbps)

@Tommi K,

I personally use a D-Link dwr-2101 WiFi-6 mobile router with the UK’s EE network, but only when travelling around the UK (camper van) and whilst the setup is not officially supported by Sonos, that will work to run Roams/Moves etc.

I also have a Huawei E5776 4G LTE MiFi device and that works with a completely different provider - so I was just curious whether it was your hardware, or the actual broadband provider that was incompatible in your case, as some devices/providers may work with Sonos products - even my iPhone hotspot will work (ID Mobile), just as another example, although I would not try to reliably run a Home system on these devices 

Some setups may happily work for one or two Sonos products. I would double-check perhaps that it’s not the provider blocking ports that Sonos may require etc. 

Hi

it worked me well for two weeks but not after that. Support told that the symptoms are just similar what they see with broadband modems. The system may work for a year or two and then suddenly stop working

they did not share any details what is the issue but for at least for us in Finland, I have tried two different mobile carriers and it is the same results. They should not block any such traffic. I work for network security so I am pretty much aware what they are doing in the network filtering

Have you tried using a different DNS? Maybe try using the usual Cloudflare, or Google public DNS servers and see if that resolves your issue.

Sonos Support routinely and incorrectly inform users that Sonos cannot work with 4G / LTE routers.

This setup is indeed "unsupported", but as @Ken_Griffiths has already said, that does not mean "will not work".