I used to have my Sonos Amp connected to my Pro-ject turntable (debut III with preamp). I moved my Amp away and recently also got a Sonos Port. I connected my turntable to the port and want to use it as an input for the record player.
 

But the audio keeps dropping, at some point my system goes total haywire. Most Sonos devices totally drop out and are missing from the system and after a while come back. Today it even when they came back claimed two S2 products (Ikea speakers) where incompatible with S2 and after a few more minutes they did show up normally again.

This is my setup:

Pro-ject recordplayer line into Sonos Port

Sonos Amp 

Sonos Arc + Sub + 2 Sonos Ones SL

2 Sonos Ikea speakers

Sonos One

Sonos Play:1

Sonos Roam

Sonos Boost

The port is NOT connected to any receiver and just functioning as a line in for the turntable.

I try and play the line in on the Arc, Play:1 and/or Amp. Lots of drops of the sound until it all goes haywire.

When it goes haywire it seems like mostly the products who use the Boost disappear. I know my One is on the wifi network directly and so is the Port. The odd thing is my Arc also disappears and that one is wired.

Any tips or ideas what I can do?