I did all the steps suggested

after i re connected the router, for few seconds, i could see the system and the rooms and everything on my phone ..but i could not control it 

after few try again the message. “can not connect to sonos”

If all the ‘missing’ Sonos products are listed in the ‘About My System’ and it’s a controller ‘discovery’ issue and you are able to ‘ping’ the missing devices, showing that they are present on the LAN (subnet), then maybe something in the detail/info. below may help you to find an answer to your discovery issue…

The discovery of the Sonos products by the Sonos controller is a slightly complex area to explore, but briefly… 

SSDP (the UPnP simple service discovery protocol) is used to initially discover the Sonos players and is done via multicasting via UDP to 239.255.255.250:1900 and, for good measure, broadcasting to 255.255.255.255:1900. 

Thereafter communication is unicast.

Both the Sonos players and controllers must share the same network subnet. However if the Sonos devices are connecting to multiple access points, the recommendations (from myself) are that they be set to the same WiFi channel and channel-width. This is for optimum performance particularly in groups and for some reason, if using, with some mesh-based WiFi systems, it appears some will work okay with Sonos, but others may not, particularly if the satellites/AP’s are perhaps auto-selecting their own WiFi channels …and to help solve any issues arising, many here in the community often suggest using SonosNet (wired mode) for Sonos device-discovery/communication instead. 

Quite possibly in your case, the router SSDP multicast used to discover your Sonos speakers is ‘perhaps’ sometimes not working as it should be. However I’m not certain of all the detail of your present network setup, but maybe (just for test purposes) try to ensure ‘all’ (Sonos products and controller devices) are using the same (router) wireless access point and WiFi band, if that’s practicable?

Note, that network switches (if applicable) can also have a role to play in device-discovery issues too and perhaps are not correctly forwarding the multicast packets across the LAN. Just check if any of the missing devices link back to any particular network switch and see what happens when the switch is bypassed.

See this useful link aswell (worth a quick read) re: IGMP snooping: https://community.fs.com/blog/what-is-igmp-snooping.html

It is also worth trying/fixing one of the three non-overlapping WiFi channels 1, 6 or 11 on the local router 2.4Ghz WiFi adapter, just to see if one of the channels may work better for you (but that’s assuming no Sonos products are wired to the LAN). Note too, that the SonosNet channel (when wired-mode is being used) should not be the same as the chosen router channel.

Another important area to explore is the controller device itself. Temporarily disable any security/software on the mobile controller as that can impact on discovery issues, for example, I’ve seen some users mention ‘Private Address’ (MAC Spoofing), or ‘WiFi calling’ VPN/Firewall/Antivirus software, mobile data access by the Sonos App etc. which has caused them some Sonos device-discovery issues… disable these features temporarily to see if that helps.

Some features built into routers can also be problematic, three that spring to mind are ‘QoS’, ‘Airtime Fairness’ and ‘Parental Control’ - I would choose to personally disable those features, if present.

I would also check for any router firmware updates or, as a last resort, maybe consider switching the router for a different brand, or model, otherwise you may just encounter the same ‘discovery’ issues from time to time, no matter what you try to do with your wired, or wireless, devices.

I’m really sorry for the lengthy post here, but maybe something mentioned above may help you to resolve the matter, if indeed it is a device-discovery issue?

This is a phone issue, surely? One phone works fine. The other doesn’t (or does initially, then stops).

I’d suspect a VPN or a cellular data “assist” function.