Hi.  That is unusual.  Can you explain a bit more what you mean by “gets unconfigured” please?

Also, please submit how your network is configured. Are there range extenders involved, is it a Mesh, are there WiFi wall plug-ins involved and your ISP name and router/ modem model. BTW… are your devices iOS or Android.

The system works perfect when I configure it, but after a while the app does not recognize any speaker and I have to reconfigure everything.

I have a mesh network extender with ZTE Router and I use IOS

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OK…So correct me if I’m in error…..

You own your ZTE router connected to your ISP’s modem. Then you have extenders wirelessly connected to your router to create your Mesh. Is that correct? If not please explain a bit further on the actual setup of your network.

That's correct, the only difference is that the WIFI extenders are connected to the router by cable.

There in is the issue. Appears your extenders are in “router” mode instead of “bridge” mode”. As such the extenders have DHCP capabilities to assign IP addresses. 

Therefore if your iPhone connects to your router your speaker may be connected to an extender and being assigned a different IP address that is not recognized by your router to which your device is connected to. Subsequently the speaker does not appear in the app.  
 

You can test my theory by unplugging your Sonos speakers. Disconnect the Extenders from your router and power them off. Reboot your router and let it come back. Plug in your Sonos speakers and let them come back. Delete and reinstall the Sonos app. Open the Sonos app and connect to an existing system. You should be able to see all your Sonos speakers. You will also be asked to sign in again to use all Sonos features.

Let us know the results.

I think @AjTrek1 must be on the right lines here.  Sonos just doesn’t “unconfigure” itself.

Today I performed the procedure and the speakers work without problem. 

@AjTrek1  Thanks for all your support