1. The battery level may be low. To check the battery level, enter Setup mode by holding the Mode button for 1-2 seconds, then press the Battery Meter cell. The light in the cell at the bottom row that corresponds to the current level will illuminate.
Solution: Plug in the AC adapter and recharge if the battery level is too low. If this does not correct the problem, or if LEO appears frozen, you can reset LEO (see below).
2. You may be using a mono headphone with LEO.
Solution: Change to using a stereo headphone, as a mono headphone can produce unexpected results when connected to LEO.