Troubleshoot.
The four things that go wrong most, and what to try.
It won't connect
Open Windows Bluetooth settings and check that your phone is listed as paired. If it isn't, turn Bluetooth off and on again on the phone and pair it once more. Then open Synfonos and try again.
No sound comes through
Start playing something on your phone first, then look at Synfonos. Check that the phone slider in Synfonos is turned up and the phone's own volume isn't at zero. If your PC can't receive phone audio, Synfonos tells you: “This computer can't play your phone's sound.”
Sound plays from the wrong place
In Synfonos, pick where you listen: headphones, speakers or USB DAC. If sound still plays from the phone's own speaker, the phone isn't connected yet, so reconnect it from Windows Bluetooth settings. Windows can switch its sound when you plug in new headphones, so check your choice again after plugging something in.
It keeps dropping
Keep the phone closer to the PC, with fewer walls in between. Other Bluetooth devices nearby can get in the way, so disconnect the ones you aren't using. Synfonos reconnects when your phone comes back, so a short drop fixes itself.