Removing false positives in Uptime

Occasionally Glow reports a site as down while the site loads perfectly for you. There are two common reasons, and they need different fixes.

First, check whether it is actually a false positive

A site can return an error status while still rendering a normal-looking page. Your browser shows the content and says nothing; anything reading the response properly, including Glow and Google, sees the error.

Open the site’s Uptime tab and read the reason we recorded. If it names a status such as 500 Internal Server Error or 502 Bad Gateway, the site really is returning that, and it is worth fixing rather than dismissing. A quick check: load the page with a query string on the end, for example ?test=1. If that returns a healthy page and the plain address does not, something is serving a cached error copy.

Second, our monitor may be blocked

Firewalls, bot protection and security plugins sometimes refuse automated requests. The site is up, it is simply refusing us.

When that happens Glow shows a notice reading “Uptime monitor is being blocked” in the uptime section, and does not alert you for an outage.

Our monitor access guide is the place to fix it. It covers both reasons a site refuses us, which need different fixes, the exact rules for Cloudflare and common security plugins, and a shortcut if the Glow plugin is already installed. The short version is one IP address, 18.171.1.94, and the user agent GlowMonitor.

Certificate errors

An expired certificate, or one that does not match the domain, is reported as downtime. That is not a false positive: browsers refuse to load the site, so visitors cannot reach it even though the server is answering. Renewing the certificate clears it.

You may see this while a site loads fine for you, because your browser can hold a cached certificate or an HSTS exception that a first-time visitor does not have.

If a site legitimately runs without a valid certificate, certificate monitoring can be switched off for that website under Uptime, Settings.

Still seeing it?

Send us the website and roughly when it happened, and we will look at exactly what our checks received. Contact support.