Music Not Playing From Speaker Pairs

To resolve most issues with speaker pairs, restart your Echo devices.

Restart your Echo devices by unplugging and then plugging them back in.
Check that you are playing supported music content. Line out and Bluetooth connections are not supported.
Make sure that the paired Echo devices are online.
Make sure that you have requested music playback on the correct, paired Echo devices.
Ask your Echo device to play a song with heavy bass to test the connection.