Try turning the hub off/on
I've just put our hub 3 into modem mode to use a different router - it was 'reluctant' and took a few reboots before it worked properly.
Then my D-Link router didn't get a WAN side IP address (though when connecting a windows laptop to the Ethernet port on the hub it did get one) - rebooting the Hub 3 again fixed that.....
And my hub's LED shows red in modem mode - certainly wouldn't call it 'magenta'.
See if you can log into the hub at 192.168.100.1 - and not 192.168.0.1
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I know a bit about Wi-Fi, Telecoms, and TV as I used to do it for a living but I'm not perfect so don't beat me up... If you make things you make mistakes!