The available device button works (i.e., it shows the appropriate list of available devices and this list refreshed as I added devices) as does the playlist button (i.e., it shows playlists from my iTunes library as included in Spotify). In looking at the console, I am seeing the following errors as I click the controls:
Error: Request failed with status code 403
exports https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js:2
exports https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js:2
onreadystatechange https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js:2
exports https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js:2
exports https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js:2
exports https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js:2
promise callback*r.prototype.request https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js:2
exports https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js:2
controlPlayer https://run.sharptools.app/custom-tile/TGAt5oIiwxBht5KCp04R/?renderToken=XXXXX:404
onclick https://run.sharptools.app/custom-tile/TGAt5oIiwxBht5KCp04R/?renderToken=XXXXXX