I recently bought a Sonos sound system, connecting to my home Wi-Fi. The day after I set the Sonos up, when I arrived home and my phone connected to my home Wi-Fi, Norton gave me a warning to say that I'd made an unsecure connection. This confused me, as I'd never had that message before, and my home Wi-Fi is still password-protected etc. Norton gave me that same warning again around a week later. On my Norton app, my Wi-Fi Security rating is now only 70%, which apparently "requires my attention", but my home Wi-Fi is still password-protected. What more does Norton want me to do?
If you check the Sonos documentation, it should tell you how to find the wifi id for that device. Maybe check the bottom of the device to see if the serial number or model number matches the numbers you see connection information. See if there are any security settings you can make on the Sonos. ie changing the default user name and password for connecting to the Sonos system.
The warnings are just a notification that you have connected to, or sometimes even just been close enough to an unsecured network. If in fact it is because you have connected to the Sonos as part of the system setup, you can ignore the warning.
It does give me a series of letters and numbers, which I guess may be the details of the unsecure network? It begins with the letters SNS, so I wonder if it is something to do with the Sonos?
If you tap on the warning, are there any other networks listed? Have you ever connected at a Starbucks, or Walmart or other free wifi network?