Diagnostics or Health Messages

the URL being checked is malformed, private, or not reachable as expected

confirm the site URL

confirm it is public if external testing is required

the plugin could not complete a health or test request

retry later

check firewall, CDN, DNS, or server restrictions

the plugin received a response, but not the one it expected

clear caches

test again

check whether a proxy or firewall is altering responses

a request returned nothing useful

inspect logs

confirm the tested endpoint is reachable