So this is partly a question, but also a report. I am relatively new to Sonos and I hadn’t experienced any of the issues that have plagued others since the new app came out, until now. The TL;DR is:

• Sonos speakers all disconnected from Unifi AP when channels were changed.
• I was eventually able to reconnect them, but received frequent false reports of an incorrect Wi-Fi password.
• Another channel change disconnected devices again. An Era 100 did not reconnect.
• Nothing I tried would get it to reconnect until I set a shorter Wi-Fi password.

The long version:

I recently switched to Unifi and set up my network based on recommendations for Sonos, even though none of my devices can use SonosNet. My speakers are all wireless. The move went smoothly and everything worked fine for a week or so after I updated each of my speakers to the new Wi-FI network.

A couple of days ago a most of my speakers went missing. When I checked Unifi I saw that they had all disconnected from the Wi-Fi network. I soon noticed that this had happened right after UniFi did a scheduled channel optimisation. All of my other Wi-Fi devices reconnected without issues, but none of the Sonos devices reconnected.

I tried to update their network to make them reconnect, starting with an Era 100, but I kept having trouble with it not being able to connect to the Wi-Fi network, seemingly because it thought the password was incorrect. It definitely wasn’t, and eventually it reconnected. By that point all my other devices had reconnected, possibly because I had updated the network details on one of the speakers.

Today the same issue happened again. I had turned off channel optimisation but last time it must’ve chosen a DFS channel and my AP had automatically changed channel because radar was detected. Most of my devices reconnected this time, including all my Sonos speakers, except one – an Era 100. This time I tried just disconnecting and reconnecting the power. That didn’t work so I tried updating the network. This time no matter how many times I tried it just refused to connect to my Wi-Fi. I resorted to a factory reset and tried adding it as a new speaker, but it still refused to connect. Again it seemed to think the password was incorrect. It was not.

Interestingly, in UniFi, under the Connectivity tab for the AP, several of my Sonos devices were listed with multiple WPA authentication failure errors from different times unrelated to this incident. These devices were all on the network, so they had the correct password.

At this point I remembered this Reddit post about long Wi-Fi passwords. My password was 22 characters, so as a last resort I updated the Wi-Fi password to a 12 character password. Everything disconnected, which was expected, so I reconnected my phone and opened the Sonos app. No network was detected, so it offered to update the network on my devices. I went through these one by one and they all connected without issue. Finally came the Era 100 that had previously been causing issues. Since it never reconnected it was in new speaker mode and I had to add it as a new speaker. This time it worked the first time.

What’s going on here? Why am I having so much trouble with Wi-Fi authentication? Was it really the password length? My old password didn’t have any special characters that my new one doesn’t, so it’s not that.