X_SCRAPE_HOST_BLOCKED
Means
the page asked for a host allowHosts does not list
Typical cause
terminal. A third-party asset, an analytics beacon or a redirect off the allow-list. The allow-list is default deny, so silence blocks. Also raised on the HTTP leg when a host only a wildcard ('*', '*.example.com') admitted resolves to a loopback, private or link-local address — the cause names the address class, never the address
Fix
add the host to allowHosts on the scrape() definition — cause names both the requested URL and the current list; for an inward host, name it exactly