Check DNS, HTTP/HTTPS, SSL and redirects together to find the next resolution step.
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| Type | Status | DNS records |
|---|---|---|
Last attempted address:
No HTTP response received
| Target | HTTP | Duration (ms) |
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These browser errors mean that the domain could not be translated into an IP address. Read A and AAAA separately: NXDOMAIN reports a missing domain, while NODATA refers only to an empty record type. A timeout does not mean missing records.
For your own site, verify A/AAAA addresses, the record name, nameserver delegation and domain registration. A site can work with only A or only AAAA records.
Compare resolvers in the DNS tool. New records may differ because of TTL and caches. If this server can reach the site but your network cannot, try another network and check the domain spelling and your DNS settings.
A DNS address does not guarantee a responding web service. TIMEOUT means the check exceeded its allowed time; CONNECTION_ERROR means a connection could not be established. Neither alone identifies a firewall, load or routing problem.
Read HTTP and HTTPS separately. Statuses 200–299 indicate success; 403 may be an access rule, 404 a missing address, and 5xx a server or proxy error. A responding root address does not prove that authenticated pages or browser application code work.
Repeat from another network. The administrator should check logs at the measurement time, ports 80/443 and resource use. A single measurement does not establish an outage for everyone.
HTTPS checks keep trust verification enabled. The certificate result lists trust, SAN hostname and date checks separately. An expired, mismatched or incomplete certificate chain may block the connection.
Find the failed check in the SSL tool. Renew for the correct domain, install required intermediate certificates and check port 443. If no certificate could be captured, review DNS and connectivity before treating it as invalid.
With a proxy such as Cloudflare, the public certificate may belong to the edge server. A valid edge certificate does not validate the origin certificate; review origin configuration with your provider for errors 525 and 526.
REDIRECT_LOOP means an address appeared again. Conflicting HTTP/HTTPS or www rules, or differing application and proxy interpretations of HTTPS, can create a loop. Read the observed addresses and statuses in order.
Define redirects in as few places as practical and use one canonical address in your application, server and proxy. Fix a missing Location header. Reaching the redirect count limit alone is not proof of a loop.
This tool follows at most five redirects and validates every target again. Private addresses, other ports and non-HTTP protocols stop the check; previous responses are preserved.
A 522 observed with Cloudflare markers reports a timeout between Cloudflare and the origin. DNS and public certificate checks may pass while the origin connection fails.
The owner or provider should check origin service and load, the origin IP in Cloudflare, and firewall rules permitting Cloudflare IP ranges. Match the measurement time to logs. We cannot confirm the exact cause without origin configuration access.
Cloudflare 526 reports that the origin certificate could not be validated. A valid public edge certificate does not rule this out; the external SSL check does not directly inspect the origin certificate.
Verify origin certificate dates, SAN hostnames and the complete intermediate chain with your provider. Install a trusted or appropriate Cloudflare Origin CA certificate. Fix certificate issues while keeping trust verification enabled, using the official guide.
Cloudflare 520 reports an unexpected origin response, 521 a refused connection, 523 an unreachable origin, and 524 a response that did not finish in time. 525 concerns origin TLS handshakes; 530 needs the additional error page 1xxx code.
Open the official source for the observed code. Match origin logs to the measurement time and request; verify DNS, firewall and TLS settings with your provider. This external measurement cannot access origin configuration.