Likely the dehumidifier unit is broken. Nothing unusual, happens to many dry cabinets sooner or later. These units are not built for eternity.
You can check with the service partner whether they have a replacement. The dehumidifier can easily be removed by loosening the 4 (or 6) screws.
In the meantime get a Thirsty Hippo to keep the humidity lower.
If there is no service center available, best to get a new one and use the existing one as storage cabinet for equipment that can stand the humidity (flashes, battery grips etc).