Xstick setup wierd behavior

XCTU gives this error message when I try to read the modem information with enable API checked:

Failed to enter command mode
Unable to read Version (ATVR)
Read parameters…Failed.

and this one after the info display requesting a reset , with API unchecked:

Failed to enter command mode
Check Com Port and Baud settings and try again.
If read problem continues select modem type and ‘Always update firmware’ from controls above and click on ‘Write’ to force firmware update.
Read parameters…Failed.

The wierd thing is , it sometimes updates the firmware when an XBee pro S2B is connected to another computer with an FTDI cable.

Can anyone tell me how to resolve this?
Is the xstck XU Z11 a XB24-ZB modem type in the dropdown list in XCTU?

Mine is running XB24-ZB ZIGBEE ROUTER API.

You never want to put end-device firmware, or enable sleeping in the xstick as the PC driver has a very hard time dealing with that. Since it has no reset button, it can be bear impossible to get XCTU to talk to the xstick when sleeping is enabled.

It is recommended to use XStick with Router firmware than end device. If the XStick is programmed as end device, it may required several continuous retries to talk to the XStick since the end device sleep.