We cannot rule out a hardware issue with CONNECT. Will CONNECT play online music services?

Even though Line-In and Line-Out live in the same ‘box’, they are separate services on the network. There is no direct connection between Line-In and Line-Out. Are you Grouping CONNECT’s Line-In with other Rooms? If so, build the Group starting with CONNECT. This will minimize Group network traffic.

Thanks for the quick response! This is happening with none of the Sonos speakers added - just the good old-fashioned non-powered speakers. Does that information point in a certain direction?

I’m a little more suspicious of a CONNECT hardware issue. Submit a diagnostic, note the confirmation number, and follow up with SONOS support. Also make sure that a source other than CONNECT successfully plays through the amplifier.

I’d also try removing the phono’s cables to the Connect and trying a CD player or other line-level device there to be sure the input to the Connect is working properly.

I am tracking along the same thinking. The connect-amplifier-non sonos speaker pathway is cutting out whether it's line-in, trying to play something from my NAS, or a streaming service. I'll bypass the connect to check my amplifier and if that is fine I'll read up on how to submit diagnostics to Sonos. Thanks everyone!

The analog output stages of those units has been known to fail. Try running one of the digital outputs through a budget DAC.