I never had a problem with this until a few months ago. Now it seems like every time I leave my house I get the poor connection error when trying to use roon arc. Everything is fine when I go into arc settings on the desktop roon app. It says ready with the checkmark and I have opened the corresponding ports on my router. I have the mobile app set to bandwidth optimized. Also whenever I get this poor connection error I can pull up the same song/album on plexamp and it plays just fine. i’m not sure where else to look. I have reinstalled the app, cleared the storage on android. I even changed the port it was using and that seemed to work for about a day and now its right back to poor connection every single time.
There are some common issues that Roon is working on when switching from your home WiFi to cellular. Try waiting to connect until you have a solid cell signal. Quit the app and restart if needed.