My xbee can no read.

I used two Arduino to do the XBee transceiver experiment, but I can not read the modem through x-ctu, he suggested,
Failed to enter command mode Failed
Connections and try again. Check
Read parameters…Failed.

I have been install the Arduino and the driver on the operating system , including Arduino driver USB to serial interface, isn’t it…
How can I do?

which board are you working with in order to read the XBee from the PC with?