When I used my mobile hotspot (using 5g as wifi was turned off) it's using a different dns yes? And that has the same problem. Or am I mistaken. I have nowherre near the knowledge of both of you so not trying to come a cross like a know it all, as I'm far from it.
Yes I'm just using my ISP dns on my router (the usual connection). I'll look into this some more.
I have a vpn installed on the chromecast but it's not activated and I have also included exemptions for channels (amongst most apps and local traffic). Potentially maybe I should uninstall that to see if it fixes it just in case it's doing something to channels traffic?