Thanks for confirming that. I'm sorry things still aren't working. Please ensure you are connected to your Home Network, and don't have any 3rd-party equipment (such as a Router) connected, and ensure your Hub is in Router Mode. The app also won't allow the connection if you're on a Guest network, VPN or Mobile Data.
If, after checking those, you're still having the problem, try clearing the data within the Connect App. These steps will help you do that:
For your Apple device, you can try this: Open Settings > Tap your name > Tap iCloud > Tap Manage Settings > Tap the Connect App > Tap Delete Data.
For your Android device, you can try this: Open settings > Apps > Connect App > Storage > Clear data / Clear cache.
If this also fails then please be aware that our teams are currently aware of an ongoing issue, that is causing the app to not recognise the Hub in a minority of instances. The team are investigating and working on fixing this as a high priority.