Hi there, new HA user here, since yesterday.
Am struggling to get the custom integration for my doorphone working.(found here).
I’m confident that I’ve followed the instructions 
but cannot get HA to authenticate when trying to add the device. I can successfully execute commands via the 2n API via a browser, however, when trying to login via the HA pop-up, I’m greeted with “Unknown error”
Any suggestions to allow me to at least go from Unknown to Known?
Cheers.