XBEE 1mW up and running,but, I cant comunicate any more

Hello, I bought the XBee 1mW Trace Antenna - Series 1 (802.15.4), and I set up as a transmitter and the other as a receiver to operate the mouse design with accelerometer like project DIY. It worked very well. Now I want to change the configuration,but, just only one xbee communicates with the x-ctu, the other can not communicate, it up and running,but, I cant comunicate any more. My question is: there is a faulty XBEE ? Do you know what i can do?
Thanks and sorry for my bad english.

Try following the steps found at the link below

Module Recovery

However, instead of writing new firmware to the radio, replace the “Writes” with “Reads”

This should allow you to read the radio.

If this doesn’t work for reading the radio, then try it for recovering the radio (following the instructions exactly, no alterations)