Almost always this is distance or something solid in the way rather than a setting, which is frustrating but usually sorted out in a few minutes. Chatter 2.0 has no channel or frequency to choose, and unlike the original Chatter there is no screw-on antenna to tighten — the antenna is built into the circuit board — so there is nothing to misconfigure.
Work through this:
Check both units are switched on and have fresh batteries. Chatter runs on replaceable batteries rather than a rechargeable one, and a flat set is the simplest explanation — fit fresh batteries and try again.
Try them close together first, about ten metres apart with nothing between them, ideally outdoors. If they talk to each other there, the problem is range and obstacles rather than the hardware.
Count what is in the way. Thick concrete walls, metal structures and whole buildings cut LoRa range hard. Indoors, moving nearer a window or reducing the number of obstacles between the two usually helps.
Check the other unit is in your contact book. Messages go to a contact you have added, so each unit needs the other one in its list.
Restore the firmware on both units. Connect each one to a computer, go to code.circuitmess.com and click Restore firmware. That rules out a half-finished upload, or a CircuitBlocks program of your own running in place of the stock messaging firmware.
The range to expect: up to about 2 km (1.2 miles) with a clear, unobstructed line of sight, and typically a few hundred metres in built-up areas. If you are getting roughly that, the units are working as designed.
If they still will not find each other outdoors at short range, message us here, or email [email protected], with your order number and photos of both circuit boards, front and back with the casings off, and we will take it from there.