I just installed zap2epg and was going through the configuration process. I was confused as I configured it with the username and password for TVheadend, but it kept saying 401 unauthorized. I was scratching my head because I knew it was correct, so I ended up changing the IP from 127.0.0.1 to the IP the DHCP server gave my my CoreELEC system and now it works.
Is there a security setting I’m missing somewhere in CoreELEC that doesn’t allow connections to the loopback address? I’m presuming if it was a zap2epg issue it would be more well known and posted on the Kodi forums for the add-on support.