The Bluefly v23 models should be connected to a computer with a USB-C to USB-A cable for data transfer or charging, or to a stand alone charger.
The Bluefly does not implement the full USB-C power delivery protocol. This design choice was made to ensure that the Bluefly is compatible with the widest range of devices to provide power. USB-C devices do some negotiations with the USB-C hosts before the host provides power.
If you really need to charge from a USB-C port on a computer or charger then you can use a USB-A adaptor. In this configuration the adapter contains the appropriate resistor and smarts to make the USB-C port on the host behave like an old USB-A port.
Without power provided by the USB-C port on the host charging will not work and the FTDI chip on the Bluefly will not be powered to enable data transfer.