X_OUTBOUND_HOST_BLOCKED
Means
an outbound HTTP call refused the address it would reach
Typical cause
dial: 'public' refused the URL: not https outside a local environment, credentials in the URL, a host that resolves to a loopback, private, link-local or reserved address, or a redirect hop that does
Fix
use a public https:// URL for meta.vendor, or dial: 'named' for a host the app itself names in code