Cannot Connect to Drayton Heating

I’ve just installed the Drayton Wiser 2 system. I’m using OpenHab 3. I’ve installed the add-in from the link on my openhab local webpage.

I connected to the Heat Hub using it’s local network and then accessed from my phone browser.

I have the secret code which is very long. (I’ve verified it using a capture app on my phone)

I tried to set up a heat Hub Thing and pasted the secret into the auth Token field on the create form, but I’m getting an authorisation error - "HTTP protocol violation: Authentication challenge without WWW-Authenticate header.

Here’s the code for my thing:

UID: draytonwiser:heathub:ebf05057bf
label: HeatHub
thingTypeUID: draytonwiser:heathub
  refresh: 10
  awaySetPoint: 16
  secret: RbvaPjpxoeifkJAygW6JgECSnya6dDBK/KuPQYJNVXuGnZmZatqAAOZJFKyMDbgidDxfWRBcZhRXRtyWHCPmxcwKU95dPWpMZljnASA3jKnF7HxVpixYHEv/Am/Su8Np"

Any pointers?