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My site is up but shows down

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You open the site yourself and it loads fine, but HostTracker reports it down (or shows a certificate/content error that doesn’t match what you see). The most common cause is that something in front of your site - a web application firewall (WAF), a bot-defense service, or a CDN’s challenge page - is blocking or challenging the monitoring checkpoint’s request, while your own browser sails through.

Why this happens

Section titled “Why this happens”

Automated protection services often treat requests from data-center IP ranges (which is where monitoring checkpoints run from) with more suspicion than requests from residential or mobile networks. A checkpoint may be:

  • Served a CAPTCHA or JavaScript challenge page instead of your real content (the check then fails a content/status check even though the page “loaded”).
  • Blocked outright by an IP or ASN-range rule, which looks like a connection failure or a 403.
  • Rate-limited, which looks intermittent rather than constant.

How to tell this is what’s happening

Section titled “How to tell this is what’s happening”
  • Failures cluster on the same one or two checkpoints every time, rather than spreading across your monitoring locations.
  • The check log shows a response that looks like a challenge/CAPTCHA page, or a flat 403/406, rather than a real error from your application.
  • The failure is consistent and repeatable from those locations, not random.

Open the failed check’s details (the snapshot, where available) to compare what the checkpoint actually received against what your browser sees. Through the API, GET /monitor/{id}/result/{resultId}/snapshot returns that raw captured response for a specific result (the check log gives you the result id); the plain result read carries the error text and, for HTTP-based types, the status code.

How to fix it

Section titled “How to fix it”
  1. Allowlist HostTracker’s monitoring checkpoints in your WAF, firewall, or bot-defense rules, so their requests skip the challenge. HostTracker’s agent addresses are published so you can build this list.
  2. If your protection service can allowlist by user agent instead of IP, that works too, since checkpoint IPs can change over time as the network grows.
  3. If you can’t or don’t want to allowlist globally, you can change which locations a specific monitor uses - see Set your default locations - to avoid the checkpoints your WAF is blocking, though allowlisting is the more durable fix.
Section titled “Related”