The addon supports MythTV Backend version from 0.27 up to 29. It inter-operates with the REST API and the protocol provided by MythTV backend. Allows streaming of Live TV & Recordings, listening to Radio channels, EPG and Timers.
To use it first you have to enable the API services of your backend and check network configuration by running mythtv-setup. 
Set the security pin as "0000"
Set the IPv6 address of the backend as "::1" if you haven't IP6 network infrastructure, which is mostly the case.
Any IPv6 addresses as "fe80::..." are not usable. Only if you have valid IP6 network infrastructure you could set address assigned to your backend. Otherwise addon will not connect properly.
You could check for your issue in section Troubleshooting.
Regular issue is none of channels have been retrieved due a data corruption. The addon had choked on a channel with an invalid character in the name or call sign. Editing the channel name or call sign in the MythTV backend will fix the issue.