Try the following:
Connecting the USB recording device.
AMETHYST USBClient does not record
Swop out the following to check for faulty equipment:
USB tap
USB cable
Flat phone cable
Telephone base
If the flat telephone cable is not connected securely into
the base of the phone it will not be able to trigger the
USBClient properly to start with the recording.
Plug the PC into a different power supply
Use the procedure in suggestion 1 after swopping out any
equiment.