As soon as I posted the above, I checked the app and searched for “Port” and the Line-in showed up. so there you go...
Can you not just enable the Autoplay Line-in setting so you don’t have to select Line-In each time you want to listen to your turntable if it has a habit of not showing in the app.
It certainly suggests a network issue of some type, such that the controller app is having trouble finding the Port. Unfortunately, not enough information to guess why. Have you submitted a system diagnostic within 10 minutes of experiencing this problem, and called Sonos Support to discuss it? Don’t post the resulting diagnostic number here, they get sensitive about GDPR.
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 Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.
Make sure that the RCA plug is fully inserted. The RCA Jack includes a mechanical switch to detect the plug. If the plug is not fully inserted or the pin is shorter than normal, the plug may not be detected. If the pin is almost detected, minor cable movement or even temperature change could cause detection to fail.
Of course we cannot rule out a hardware issue. Fortunately, over the years, there have only been a few reports of this sort.
Thank you @Mr. T - I have played with the autoplay setting and will see if that fixes it.
When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.
@Airgetlam thank you - will submit a report of pain persists.
You’re welcome.
The ‘autoplay’ function won’t fix it not showing up occasionally (or it shouldn’t, but it is software), but I suspect you’ll continue to see it come and go as your controller struggles with the network connection and finds or misses the device.