Why I cannot turn off the re.corder?

If the blue led is steady on and when you touch the RECTANGLE or TRIANGLE button the green led blinks, it means that the re.corder is still connected to something, so it will not turn off.
Try to disconnect it from the App in Settings > Devices or turn off the bluetooth on your smartphone or pc.
When not connected the re.corder will automatically turn off after 2 minutes. You can force the disconnection by pressing for at least 6 seconds the CIRCLE RECTANGLE TRIANGLE keys.