There are two things that spring to mind rather immediately. 

The first is simple wifi interference . It’s important to recognize that interference doesn’t have to come from your network itself, it can come from outside sources. I’ve had issues, at separate times, with a microwave, and a new neighbor whose router stomped all over my signal. 

The second possibility is a duplicate IP address issue caused by confusion in the router. An easy test is to unplug all Sonos devices from power, and while they are unplugged, reboot the router. Wait a couple of minutes before plugging in the Sonos.

If that does solve your issue, I’d highly recommend looking into the routers manual to determine how to set up reserved IP addresses, which can help if the router becomes ‘confused’ again. 

Unless you’re just venting, and not actually asking for help. If so, hopefully these suggestions might help other people. 

Definitely asking for help. Ive unplugged and rebooted all of my speakers each time I try to use them. I’ve reconnected my router multiple times, even had my internet company swap it out twice and change my modem once. The speakers still don’t show and I have to restart them (usually several times) before they’re even picked up by my internet. I’ve checked that it’s on the correct 2.5 v 5hz connection, my speeds are fast enough to use 50 devices at once…I’m really at a loss. I have no other connectivity issues with any other devices. 

A simple TV streaming a movie, a bunch of thermostats, phones and computers, don’t stress your network as much as a multi-unit SONOS system.

As Airgetlam suggests, “reserve” IP addresses for all regular network clients. Inside the router is a function that operates similar to the receptionist in the lobby of a building. As clients enter the network, they are given an “IP address”. This is their identification on the network. If something happens to the router table that keeps track of the addresses (similar to spilling coffee into the little box on the receptionist’s desk) the router starts over and issues new addresses. Unfortunately, there is no general notice sent out asking clients to return to the desk and have a new number assigned. You can imagine the confusion as a different set of addresses is assigned — “I didn’t order that!”, “where’s my order”, “the phone for ‘Tom’ isn’t working”, … . “Reservations” give these clients a VIP status and they will always be assigned the same IP address. Reservations must be re-established if a router is replaced. It’s best to reboot everything on the network after establishing the reservations.

Reservations is the best starting point and this resolves the bulk of issues we see. There could be other issues, such as hardware failure or a rogue device on your network that simply ignores the receptionist.

Describe your network for us. What is wired? Wireless? Network switches? Mesh WiFi? Model numbers?

Finally, refrain from SONOS Factory Reset without further consult. Factory Reset does not cure fundamental issues, wastes a lot of time, but it might accidentally, temporarily gloss over something.

Please tell us what router you have, as that seems the most likely cause for your symptoms.

As expensive as this system is it is very disappointing.  Speakers disconnect all the time.  I originally purchase an Alexa 1 and recently bought 2 era 100 and the beam.  Set up, reset, reboot, on and one.  May bring the all back