New Equity Trading API in Beta - Try it Out in Practice Mode!

Hi all,
I generated an API key for the live environment enabling all read-only scopes.

Whatever I do, I always get 401 HTTP code.
Even if I make a simple test with curl I get 401:

curl -X GET "https://demo.trading212.com/api/v0/equity/account/cash" \                 [ruby-2.3.1]
     -H "Authorization: Bearer XXX"

(where XXX is my API key)

What should I do?