Two suggestions. 

First, since it seems like it’s an issue with CEC, I’d try a reboot of the TV by unplugging  it from the wall for five minutes, then plugging it back in. 

Second, on the remote chance there is a failure in the Beam, I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, 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 pinpoint the issue and help you find a solution.

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

Hello, thanks, 5 mins unplugged didn’t help.

My number is 524743115. I’d appreciate if a moderator can take a look. Thank you

Hi @pianistul21, 

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, your Phillips TV is not sending a signal to your Sonos Beam. The steps suggested by @Airgetlam would refresh the connection of your devices.

To help you check the audio issue with your Sonos Beam, allow me to ask a few questions.

1. When you go to Browse in the Sonos app and select TV, did you get the sound from the Sonos Beam?
2. Is the TV Autoplay enabled on the Sonos app?
3. Is TV Autoplay enabled on the Sono app?
4. Check if HDMI-CEC enabled on your TV.
5. Check for TV's firmware update.
5. Adjust TV audio format and we recommend testing Stereo/PCM to see if the issue improves.
6. Use an optical cable to connect your TV to your Beam.
7. You may check out this community thread for your reference.

If you're still having the same issue, your Phillips TV may not be passing an audio signal correctly. We suggest reaching out to the TV manufacturer for further help.

Let us know if you have any other questions or run into any issues, please do not hesitate to reach out.