Tying to find the Bluetooth connectivity disconnected, I did reboot multiple times until eventually I could achieve this. Like always following rebooting I could connect the sound to my Bluetooth device, but following shutting the device off and attempting to reconnect no sound arrived into the Bluetooth device. In https://www.bluetoothspeaker.top/tws-support-tf-card-playing-music-player-bluetooth-speaker-best-sound/