If you have 5 minutes and want to avoid the same rathole, read on.
I purchased a refurb ERA 100. It came but was basically DOA. I returned it and got another refurb. This one at least tried to connect. After hours with tech support and after resetting all my wifi stuff (as well as my neighbor’s wifi, ok, not quite) I got it to connect to an existing sonos system with 4 well used and stable devices, 2 Play1’s, a One SL, and a Port. Three days later it was no longer connected. Nothing changed. Power was on, the other 4 units are still connected. So I gave up and decided to get them to honor the money back guarantee. Then things really started to go downhill. I was able to process an RO online but they never sent a shipping label. I called weekly. I chatted. I emailed, I emailed the CEO. It has been over two weeks, still no label. During the email exercise they decided that to be helpful they would cancel the RO. Still no shipping label. All I want to do is return this thing and get my $ back. At this point I am sure Sonos has spent at least 2x what the unit is worth on tech support and sales support resisting getting me a shipping label. But I am persistent.