If you are moving from openzwave to zwave-js and using the old network key in zwave-js configuration, results in error.
zwave and openzwave uses network key in the format like
0x6E, 0xD5, 0x00, 0x2B, 0xCE, 0x00, 0x27, 0xFA, 0xCE, 0xE2, 0x76, 0x8D, 0x81, 0xCF, 0xD6, 0x09
zwave-js expects the same key in
you need to remove 0x and ,.
Hope this helps