help: host_not_allowed
What it means: An http-kind spec (or call) named a URL whose host this host's egress policy refuses to reach.
Likely cause: A private/internal address, or a public host your plan isn't allowed to reach (network: "public"/"egress" needs a paid plan).
Fix: Point the spec at a publicly routable host, or upgrade via billing.checkout if the policy is the actual blocker.