We suspect that the buzzing sound is caused by a fluctuating voltage at the power source. We recommend plugging the machine straight into an outlet, rather than using a power extension cord. If the buzzing sound persists, unplug your machine from the power source, let it rest for 5 minutes then plug it back. You may also try a different main power outlet to see if the sound still persists.
If the buzzing sound is constant, please reach out to our Customer Care team.