The next time it happens, I would recommend that you submit a system diagnostic and call Sonos Support to discuss it, or post the diagnostic number here for a Community Moderator to pick up.

There may be information included in the diagnostic that will help Sonos identify the device causing the volume to change, and help you find a solution.

When you speak directly to the phone folks, there are more options available beyond just the diagnostic analysis.

Note that in all solved cases around this issue, reported in this forum, it has been an external issue. Sometimes, in older days, it was a cat sitting on a speaker, due to the heat generated by the speaker, and resting on the volume button. In other cases, for a soundbar, it’s been a remote under the cushions. In some cases, it’s been sticky buttons on phones. So far, it’s not been the Sonos software, but there’s always a first, and the more hard data you can provide to help them figure out what is going on, the better. 

hi. the Sonos Playbar sound level has been ok now for a few weeks now , but last night ( during the night )volume had dropped down to zero on the App. turned it back up half way to where we normally have it and we use the Foxtel Remote to adjust sound level ..

Only just use the Playbar on its own  , i have disconnected all Wifi devices and restarted them one at a time so they have there own ip address , updated iphone & iphone software , obviously that didnt make a difference.

submitted a diagnostics test # 361732073 , any help or ideas would be great thanks

Hi @dusan27,

Thanks for reaching out to the Sonos community. We appreciate you for letting us know about your concern and for submitting the diagnostic.

Upon checking on the report, the remote sent the signal to the TV to set the volume to 0. Other than the remote and iOs device, no other devices detected that controls the volume on your Sonos Playbar.

The diagnostic also detected that there's a high latency in the network. Your Playbar is experiencing a slow connection to the network. Let me suggest the next troubleshooting steps. You may also observe if this will address the volume issue with your Playbar. 

1. Sequential reboot to refresh your network and all your Sonos devices connection.
   • Unplug your network devices (modem, router, any wireless access points on the network) from the power and wait for 60 full seconds before you plug it back in.
   • Once the router is back online, unplug all your Sonos devices from the power. Please wait 15 seconds before you plug back them back in.
   • Force close the Sonos app from your iOS or Android device.
   • When the status light on your Sonos speakers are solid white, get back on the Sonos app and check if you're connected.
   • Test playback and observe Sonos performance.
2. Hardwire Playbar to your router.
   • Test playback and observe Sonos performance.

If still not resolved, I recommend contacting our phone support team to further look into this. Please let me know if you have any further questions or concerns, we’ll be glad to assist you. 

thanks, ive allready rebooted modem with all wifi devices off etc ...i might try a new remote to see if that helps ..if not ill just take the batteries out of tv remote 

replaced TV Remote with new one & when remote is not in use or TV is off, point TV Remote the other way so cant signal sound bar.This seems to have worked for me so far.