I bought 3 licenses to use on 3 computers and, after a lot of trial and errors, I finally succeeded setting up SSL, which I thought was an obvious necessity. ( Wanted to do the certificates with the macOS integrated assistant, but couldn't adapt the method you described on the site to their parameters. So it's detached from my Root CA)
Anyway, the problem is still that I can't use the application capacities for the security dongle Yubikey 4 (product of Yubico).
It serves to store certificates and their keys, and can be used continuously or sporadicaly depending which. That's why I thought I'd use it, because those keys have a limited capacity and I wanted to use on several computers the credentials available on several keys, the same... and to avoid copying the keys having a single one of each shared amongst the client softwares.
Here are some technical informations to identify the device :
Hope you can have a solution.