I did the check on the hub manager and there is still nothing. I will contact BT. Thank you for your suggestions
I just had this same fault display on my Advanced Digital Home Phone. But may have a solution
It claimed 'no internet connection is available' but oh yes there is as I'm using it to type this.
The Smart Hub 2 said the phone was registered and connected.
So I deregistered it and reregistered it and it immediately asked about downloading new software (takes a few minutes) and then guess what it starts working again.
So the faults appear to be