I have Volumio running on a Raspberry Pi as a standalone player. I connected to my phone’s wifi to share the Internet connection, but the Volumio app on the phone keeps saying “You’re not connected to a WI-FI Network” and refuses to see the player. I tried adding the IP address of the player manually but I still can’t see the device. I have to manually enter the player IP in the phone’s web browser, but this is not ideal.
The app is restricted to only look for Volumio-devices when the device (phone or tablet) is connected to a wifi network. If you share your non-wifi connection, e.g. 4G, with Volumio via a hotspot from your phone, the phone is not connected to a Wifi network and the app does not work.
This restriction is very annoying indeed, I’ve encountered too. I sometimes manage my Volumio when I’m out by connecting to my vpn server at home. The app stops working because the phone has no wifi, but I can access the webUI via the browser just fine.