Sparkfun Electronics USB Explorer Manual page 14

Page 14 of 16
If that doesn't fix the error, you can probably get away with typing a "0" in
that box (usually this pops up for properties like encryption keys or other
values meant to be kept secret).
After you've loaded the default values, you still need to write the settings
by clicking the big pencil icon above – .
After defaulting both radios, the addresses, networks, and other settings
should all be compatible. Try communicating over the console again.
Resetting Old (Pre-Reset Button) Explorers
When it's having trouble communicating with an XBee, XCTU may present
you with a notification like this:
The USB explorers were revised in May 2014 to include a reset button, so
resetting should be easily done on those newer boards. However, if you're
using an older Explorer you'll have to use the "jumper method". Grab a
piece of jumper wire and, when prompted with the "Action Required"
window, briefly connect the RST pin to GND.