I installed the addon today
But I've got the same error as RealZac is describing, when clicking on my device in the Spotify app on my phone, I monitored the service and it says
INFO:librespot::session: Connecting to AP "lon2-accesspoint-a7.ap.spotify.com:4070"
thread 'main' panicked at 'Authentication failed', /home/chewitt/LibreELEC.80-addons/build.LibreELEC-Generic.x86_64-8.0-devel/librespot-aa86ebf/.x86_64-libreelec-linux-gnu/x86_64-unknown-linux-gnu/release/build/librespot-e68a0fa7c741f792/out/lib.rs:365
Did I do something wrong? Wrong settings perhaps?