Chromecast not showing in Android apps

[Android Central Question]

Hi all
I've been using a Chromecast for many years.
Recently we got a new WiFi router and since then the Chromecast has been causing trouble.
I can see it in the Google Home app. It does start up and show preloaded photos on the TV screen, including its name ("Family Room TV") and the name of the WiFi network, but no time/date.
However, the Chromecast button is greyed out in all apps, and when I press it, either nothing happens or the phone starts searching but can't find any devices.
I've tried the whole range of recovery tips - restarting the router, factory resetting the Chromecast, turning everything off and back on again etc.
Any further ideas???

 

[hallux]

The new router may be the key here. New routers are generally dual-band, which means they broadcast on both 2.4 gHz and 5 gHz (many people refer to it as '5g' in some iteration, it shouldn't be confused with 5G cellular technology). It's possible the devices think they're on different networks. Try turning off dual-band mode and just using the 2.4 gHz band (compatible with more devices) to see if that helps.

Specifically - which Chromecast do you have? I have two of the latest ones (with a remote) and I have no trouble seeing them from my phone, tablet and Mac if I want to cast from one of those devices and I have the dual-band network configured on my router.

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