Sony STR-DN1080 Manual page 209

The sound skips or fluctuates, or the connection is
lost.
The receiver and the BLUETOOTH device are too far apart.
If there are obstructions between the receiver and your BLUETOOTH device, remove these
or move the receiver and/or device avoid them.
If there is a device that generates electromagnetic radiation, such as a wireless LAN, other
BLUETOOTH device, or a microwave oven nearby, move it away.
[294] Troubleshooting
The sound of your BLUETOOTH device cannot be
heard on the receiver.
Turn up the volume on your BLUETOOTH device first, and then adjust the volume using
+ on the remote control (or MASTER VOLUME on the receiver).
[295] Troubleshooting
Severe humming or noise.
If there are obstructions between the receiver and your BLUETOOTH device, remove them
or move the receiver and/or device avoid them.
If there is a device that generates electromagnetic radiation, such as a wireless LAN, other
BLUETOOTH device, or a microwave oven nearby, move it away.
Turn down the volume of the connected BLUETOOTH device.
[296] Troubleshooting
Cannot control the receiver using a SongPal device.
It may take some time for the receiver to connect to the network after it is turned on. Try
again later.
The smartphone or tablet device may not be connected to the same network as the receiver.
Connect to the same network and try again.
Also see "Controller devices or applications on the home network cannot connect to the
receiver."
Refer to the SongPal help.
[297] Troubleshooting
BLUETOOTH device
BLUETOOTH device
BLUETOOTH device
"BRAVIA" Sync (Control for HDMI)