Follow the Quickstart guide
Try a different usb cable. Not all type-C cables are made the same.
We recommend Cable Matters USB 3.1 Type C (USB-C) to Type A (USB-A) Cable in Black 3.3 Feet
This is a good USB Type C Cable that is on Benson Leung’s approved list. We also recommend it and used it during the design of the Infinity ErgoDox interconnect.
You can also try to clean the USB port with isopropal alchohol.
N-Key rollover allows you to press any number of keys at the same time.
Many keyboards will only allow you to press 2-6 keys at once, and you may thus miss some presses.