new hub Smart2 Internet/wifi working ok Blue light on Hub solid. BT states DV activated. Cannot pair DV adapter, green light just keeps flashing slowly. Plugging a phone into green phone socket does not work.
At the master socket there is still a ASDL filter should this be removed, cannot see this is the problem aas internet OK
Does the hub manager show your phone number or does it show 'not confgured' ?
If the latter, DV has not been activated yet.
The adapter won't pair to the hub until DV is active.
If BT say its activated I would treat it as such. Odd that the phone does not work in the back of the hub as that would suggest issue is not with the adapter.
I would do a factory reset of the hub by pressing something into that hole and holding until the hub light goes from blue to green (I found a biro works quite well) if the issue persists I would contact BT and have them investigate further:
Fix broadband | BT Help
i would check as @licquorice suggested to see if hub manager showing phone configured and if not then I would restart the hub not factory reset as that may cause problems with your wifi and see if that helps.