There is no benefit in resetting a unit in situations like this, as you delete the diagnostic information.  First off, have you tried touching the mic symbol on the unit in question?  Sometimes it’s easy to turn the mic off when dusting and you may need to just toggle it back on. :)

If this doesn’t work, can you open the Sonos app on your mobile device a select Settings>Services>Voice>Alexa and check that all of your devices are listed?  

Thanks for the advice on resetting. I won’t take that approach again.

I’ve opened the voice services and this device does not show up on the list. I’ve added the skill and everything is working perfect. 

Thank so much for your quick response and great advice!

Hello Everyone. I have bought my first pair of second hand Sonos One which are still under warranty. I had to do factory reset to control them in Sonos app. Mic has stopped working ever since. As long as speakers were registered with previous owner, I could mute off and mute on mic.

now, I can’t find Amazon Alexa in appstore and neither alexa voice service under Sonos app on my iphone.

I tried using android phone and installed Alexa app, linked sonos account, enabled/disabled Sonos skill and still mic button isn’t working. Alexa voice service is not available on android too.

could someone please suggest how to get mic working?

Can you tell us what’s displayed on the Sonos app on your mobile device when you select Settings>Services>Voice>Alexa?  

read some articles, looks like no voice service in Singapore :(

I just spent an hour trying everything to get a new Sonos One to work.  Thought it was defective then I came upon this suggestion.  WINNER!!  Thanks alot