It is no longer possible to create a new Tiliado account because there is no need for that.
Tiliado accounts were used to hold information about purchases/subscriptions of Nuvola Player/Nuvola Apps. To activate Nuvola, users needed to link the Nuvola app to their Tiliado account.
Nowadays, new Nuvola purchases are handled via Gumroad and users receive a license key to enter in the Nuvola app, so they don't need a Tiliado account at all.
Legacy Tiliado accounts are going to be removed: