unpossible to cast downloaded playlist to chromecast from iOs

[albourg]

Hi,

using iPadPro, iOs 11, spotify, chromecast audio.

I have a downloaded playlist. I can play it locally but I can't send to to chromecast. Message is (in French): Lecture impossible pour l'instant: Desole! Impossible de lire ce contenu si vous etes connecte a un autre appareil.(Translation: unpossible to play now: Sorry! unpossible to read this content if you are connected to another device).

I can play it locally on iPad. I can play "in streaming" undownloaded playlists from iPad to chromecast (meaning I re-download each file so I consume data). Any hint to stream my downloaded playlist using wifi to chromecast?