For how long did you wait? It can take a while sometimes.
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You have a hub max? Supported devices are shown at the app store.
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Casting stuff to a ggl hub can be done if you add it as Chromecast device.
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Take look at the community Nest app, that one has Nest Protect onboard too.
https://store.homey.community/app/com.verbem.nest
Forum topic:
Dutch howto (you can use a translate app)
