There was a problem connecting your Sonos One to ".

I will report that, sadly, this solution did NOT work for me except as a wired connection. Even after leaving it connected for a really long time, and getting a notice that the network connected perfectly to the SONOS One (while wired), after disconnecting the wire the wireless connection continued to fail with the same message above. 
BUT!!!  Interestingly, there seems to be some sort odd incompatibility between SONOS and the iOS SONOS app  that caused my problem!  The connectivity was established instantly when I used my Samsung/Google app to set up the speaker. No delays, no error messages. Works beautifully now!  Not the first set of connectivity issues I’ve solved this way, either. I’ve found that Apple apps do not always work as well as Google apps when setting up wireless devices. 

It is a very easy fix. Wish sonos listed it here.. It happens when the speaker needs an update and it has not been used for a while. It will help if you can connect the speaker to an ethernet cable instead of Wi-Fi before you begin. First thing, please make sure your speaker is blinking green. There are articles here which describes how to get your speaker to the blinking green led state. I have the IKEA version, all I have to do is press the play button, and then hold it before plugging the power cable in. This will put my device into blinking green LED state. Then you have to do is go to your IOS or Android app > settings cog wheel icon > click on Reset app.. not reset the speaker or device.. you just want the sonos iOS/android app to be reset.. this will reset the Sonos app. Next enable the mic for the Sonos app from your phone. Now close and relaunch the sonos app. It will act like you are setting it up for the first time. It will quickly find the speaker and the speaker will play a Chime. Your Sonos app will listen to the chime and connect. So enabling your mic settings is critical. After that you’ll get a notification that your speaker needs a new update. Once your new update is downloaded, you’re good to go. The problem occurred to me because I did not use the ikea bookshelf speaker for more than a year. Hope this is helpful to all

This seems to be the only solution that works

I have been on the phone twice with SONOS, for a total of two hours, reset app, used Ethernet cord multiple times, allowed mic, deleted/reinstalled SONOS app, used a different phone for the app. NOTHING WORKS! Any help, please! 

Same problem, I’ve tried everything, been waiting for a call back on my phone for 4 hours, also waiting 2hour on wife’s phone, gen one app works but gen 2 for new speakers doesn’t work, I have had so many problems with connectivity over ten years, when it works it’s great when it doesn’t it’s useless. Shop and sales are useless too.

Hey there,

I have exactly the same issues with the speaker. Spend the whole day today with trying to connect.-unsuccessfully. Actually, nothing changed on the speaker and while connecte via Ethernet cable it works perfectly. But without the cable it is not possible anymore. Years ago it was still so easy and without any sound keys etc. I am pretty sure that sonos did this by intention to sell new models and get rid of the clients that still keep their old models.

if they do not fix this problem the next 2 weeks, it was DEFINITELY my last device of sonos.

I’m having the same problem with the NETGEAR Nighthawk X4 R7500v2 and Sonos One Speakers!

I just bought an ethernet cable (so outdated) at Staples and tried that, no luck.

Yes, I did a factory reset, because I thought I needed to after changing my network name and settings. 🤦🏻

If you did a factory reset of all your Sonos products, in one fell swoop, you also need to create a new Sonos Household aswell to hold the products - but it all depends how you went about resetting the products in the first instance and which ones you cabled to the LAN. My suggestion is to perhaps contact Sonos Support and let them go through the steps with you - there should not need to be a reason to factory reset your devices, even if you change your router. Anyhow, here is the link to contact Sonos customer support:

https://support.sonos.com/s/contact

I contacted Sonos Support and they had no solutions. They told me to contact my ISP, as if they are the problem. I bought a new TP-Link router to see if anything would change. Nothing has changed. The TP-Link Router will only see a Sonos One speaker if it is connected via ethernet and factory reset. Once it is added and I disconnect the ethernet from the speaker to use it wirelessly, it disappears from the Sonos app, along with my Sonos Wi-Fi system.

So, either I wait until Sonos updates their app to work with these old Sonos One speakers, or I take them to Salvation Army and buy speakers from another company.

New router today = disaster. Sonos one no longer appears anywhere, can’t be found/located in network or anywhere else, ‘no products found’ in Manage Networks to reset WiFi network details, WiFi won’t connect, only Ethernet cable works. All WiFi 2.5ghz/5.0ghz/WAP2 checked, channel set to11, 6 and smart, etc, etc. Nothing works and nothing at all in the Sonos website solves the problem.