Scanning a QR code is not working

[hisashiyamaguchi]

I'm trying to scan QR code so as to pair my computer and iPhone. Although I'm trying to lower font on my terminal and my iPhone is capturing the code, it's not paired. I would like to see how I can put code manually.
https://krypt.co/docs/start/pair.html

$ kr -v
kr version 2.4.13
$ uname -a
Darwin tyo-mpy1d 19.6.0 Darwin Kernel Version 19.6.0: Tue Jan 12 22:13:05 PST 2021; root:xnu-6153.141.16~1/RELEASE_X86_64 x86_64

I'm using iPhone - Akamai MFA v1.0.4.28 is installed.