Hi @deano475 thanks for your post, although we're sorry to hear of your concerns raised regarding your Hub 4 failing to link with your Connect App.
As @Client62 has mentioned, if the Connect App isn't working then you might find the Hub's Settings page useful - you can access this by typing 192.168.0.1 and you can unlock a wealth of options here.
In terms of the Connect App though, the first thing to be aware of is you need to be connected to your Home Wi-Fi in order for the app to connect to the Hub. It won't allow the connection if you're on a different Wi-Fi network, Guest network on your own Wi-Fi, VPN, or mobile data. If this still doesn't help, try clearing the data within the Connect App. These steps will help you do that:
For your Apple device, if you're on iOS 15 then you can try this: Open Settings > Tap your name > Tap iCloud > Tap Manage Settings > Tap the Connect App > Tap Delete Data.
If you're on iOS 16 then just delete the app from your device, restart the handset, and then re-download the Connect App.
For your Android device, you can try this: Open settings > Apps > Connect App > Storage > Clear data / Clear cache.
If this also fails then we currently have a known error with some of the data in our systems that's causing the app to not recognise the Hub in a minority of instances. We're already investigating this as a high priority.
Pop back and keep us posted.