Unfortunately, the device has adjusted the service for some reason and does no longer make a sound.
A device that, gives up the ghost after 3 months at low stress is, unfortunately, can only be assessed as unsatisfactory.
The unit returns and may lack offer (Amazon has not in the program) will only be refunded.
Note:
The power supply still seems to be working, I once connected my phone to test and it is loaded, but that makes it not really better :(