Double check the cables/connections and make sure you are using the correct inputs/outputs. You can also check the Line Out settings for the Port in the Sonos app.

I’ve done that. Line Out Level is set to Variable. I mean it’s not too complicated...the Line Out RCAs are connected to the Line In RCAs at the receiver. 

I’ve also checked Products → Port → Network

and it says “Strong connection.”

So what’s going wrong here? The only 2 differences are the Sonos CONNECT was using a wired ethernet set up (but there’s too much interference in my condo, which is why I’m switched to wi-fi for the Port), and previously I had used to use the Sonos CONNECT optical output (but for some reason Sonos Port doesn’t have that, so I’m just using the RCAs).

Is there a diagnostic I can run?

EDIT: I tried using the Line In ports, playing from my computer, and that successfully played throughout my Sonos speakers. But then again I tried the Line Out ports, this time connected to my computer’s soundcard input (instead of my receiver), and once again there was nothing.

I’d sure be tempted to do a power cycle, forcing a reload of the OS. If that didn’t change anything, I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. But 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.

ok thanks, I appreciate the advice