Having a switch not output its expected keycode can be frustrating. Here are some tips to try when that happens.
First of all, check if you've soldered the legs of the switch itself. An easy mistake to check, and it happens to the best of us!
An entire row or column does not work
If an entire row or column does not work, check the solder joints on the microcontroller. You may have a bridge (when two or more pins are connected together by solder), or you may have a bad joint. Rework the joints as needed, and check again.
A single switch does not work
When a single switch does not work, follow the following steps.
Each switch has its own diode, often placed near it. Check that the black line on the diode is aligned with the square pad, or the white line on its footprint.
You might have a bridge. Sometimes a solder joint spans more contacts than it should. With the switches on the Kyria, this sometimes happens with the pad in the outer corner. This pad is used for choc switches, but can cause a single switch to not work when bridged.
Check if you soldered the connections of the switch. Even the best of us forget to solder those joints sometimes. Also check if the joins are formed correctly, and rework if needed.
A Defective Component
If you checked for both and your key still doesn't behave as expected, try replacing the diode, recheck, and then replace the switch and recheck.