sonos dropping out

How often? Do you have a SONOS BRIDGE in the system?  Error messages? Don’t Factory Reset without further consult.

A few times an hour for about 10 seconds, yes have a bridge 

BRIDGE failure rate is now high enough that you should assume it is causing trouble until proven otherwise. A typical failure is the power supply. A healthy supply provides slightly over 5V. Below this BRIDGE becomes intermittent, sometimes taking down parts of the network beyond SONOS.

In most cases BRIDGE is no longer necessary or effective. BRIDGE is effective when a player is too distant from other players’ wireless coverage. A BRIDGE can be placed about midway between the two areas. BRIDGE was originally developed to provide an inexpensive wired connection between a SONOS system and the network before SONOS supported WiFi. Now WiFi is supported and BRIDGE is essentially obsolete.

Check to see that the WiFi network is setup on your SONOS system. Once the WiFi network is defined, simply power down BRIDGE and allow a couple minutes for the system to reconfigure itself.

If you have to have a Bridge to get your system to work, at least replace it/them with a (less obsolete) Boost. Far better networking support and much lower problem rates. 

Used Boosts are fairly cheap.

Still better to change things around so neither are needed.

I just looked at your profile and you should simply remove the Bridge, since its is an obsolete device and hard wire either your Playbar, Play 5 or Connect to your router instead. I am assuming you are using the S1 app which has been stable. The weak link IS your Bridge at this point.

I removed bridge and system stops working? 

Did you connect one of your other Sonos devices to the cable the bridge was plugged into?

What’s the process I need to do before disconnecting bridge?

There is none. Unplug it and remove the Ethernet cable. Then connect a speaker to the Ethernet cable.

if you need a longer cable to reach another speaker, simply purchase one.

If you have been unable to add a WiFi connection to your system yet, remove BRIDGE, temporarily wire a unit to the network and verify or setup the system’s WiFi connection.