Please have a look at my post: Tips & Tricks - Resolving random issues impacting Sonos devices.. | Sonos Community

I will try this but It’s really a pain to connect my Beam (Gen 1).

All was working fine before my holidays adn one week later no connection.

In the meantime there was a new version of rhe Sonos application so I wonder if it has a relation.

I wonder too if it’s not a confilct between 5Ghz and 2,4 Ghz WIFI.

Normally the cause of connection issues after an update is that the Sonos devices boot, as part of the firmware update, and are then allocated an IP address that another device is already using but that the router has lost the allocation record when it was booted itself.

So  a single reboot of my rooter, then the Beam should solve the problem ?

Do I need a reinitialization of the soundbar ?

You’ll need to follow the steps in the linked post in my first reply, but reserving IP addresses within your router will stop this issue from happening again.  I suspect that this is network issue and so reinitialising your Sound Bar won’t make any difference.

Thanks, I followed your steps and it works now.

Pity that the installation of the products is so fastidious.

Great news. This is a Router manufacturer issue rather than Sonos but Sonos players are susceptible to it.