How to get AirPlay into my older system.

Have you tried using any of the other Sonos Ports to see if they drop out on your main system?

I have older ZP90s that I use in secondary systems that I picked up off craiglist for like $50 each. 

+1 for WiiM.  They make 3 levels of product…the Mini, the Pro and the Pro plus.  Priced under $100, around $150, and in the low $200s.  The app is very simple to use, and all have toslink out.  Be as frugal as you choose.  The use of digital out eliminates the difference between Pro and Pro Plus, which is in the digital to analog  converter. The Pro models have RCA jacks, an Ethernet port and faster processors.  I would get the Pro if I had your situation.

Pick up a older used Apple TV, one with Optical out for audio.

There is always someone selling one typically for $30 or less.

Works great for Airplay. Work’s wireless or wired. 

Thanks guys.

To answer a few questions: @jbuhl I do not have any other Sonos Ports or Sonos Connects. I have a Sonos Amp and a bunch of speakers. They all work well now except for this old Connect.

@dougsat I had an older Apple TV which was glitchy as well. Tossed it a while back. Maybe the issue is the Oppo?

@crustycoot I will look into the Wiim but not sure I understand the advice to get the Pro. Since the Mini has optical out what benefit would I get with the Wiim or Wiim Pro over the Mini? Will the faster processors make any difference? I would not have any need of RCA jacks or ethernet.

@audphile1 , why would the quality be better using the Wiim app verse Qobuz via AirPlay?

Also, I came across the Belkin Connect Soundform Connect. Cheaper than the Wiim Mini. CD quality only but to be honest I never hear any difference above CD quality anyway. Anyone have experience with this device?

Let me know if you decide to take up @dougsat suggestion.  I think I have on old appleTV box I could part with for $30.  It do gots the optical out.