As mentioned by Ernie_C, streaming via the Chromecast won't work.
The app has a built in feature that blocks streaming when using another output. The only place you can stream is on the actual device you have registered. Anything other than that will through up an error code that you're currently seeing.
Chromecasts are not supported and as far as i'm aware, we won't be supporting it. If this does change then we will let you know
Kath_F Forum Team
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