Hey folks, first of all I’d like to thank @jasondefuria on his work on updating the Lyric component.
I was getting the dreaded code 400 error when I noticed my configuration URL was using my public Nabu Casa web address (remote control) even though I had configured the Honeywell API to use the internal IP.
I was able to get it working by temporarily disabling remote control in Home Assistant configuration. So for those using @jasondefuria’s repo, try disabling remote control so it does not get passed in as the remote URL.