QPST configuration window can not find the phone.

Q) Why configuration window can not find the phone while the DIAG COM port is available in the device manager?
A) The phone is connected to the PC. But the connectivity in the phone is not completed to the DIAG task.

Details:
When DIAG port is available in the device manager, USB DIAG port enumeration is successful.
To find the phone QPST sends certain DIAG commands.
If DIAG does not response, QPST will assume there is no phone available and display "No Phone".

The most likely reason for this is that DIAG service may be mapped to NULL port in the device.
Please check whether port is mapped or not with rdm_current_device_map[] array.
rdm_current_device_map[RDM_USB_DIAG_DEV] = RDM_DAIG_SRVC;