Why does is-down say a site is up when I cannot reach it?
When the is-down tool shows a site as up but your browser cannot load it, the problem is almost always local: DNS cache, ISP route, or firewall.
Quick answer#
Our probe runs from an external cloud region. If it says the site is up but your browser fails, the outage is between you and the site — usually local DNS, ISP routing, or a corporate firewall.
Fast checks to run#
ipconfig /flushdns (Windows) or sudo dscacheutil -flushcache (macOS)Where to find it in Lemwatch#
/is-down/<domain> — compare our result to your browser.
FAQ#
Can Lemwatch probe from my region?#
Multi-region probes are on the paid plans — see uptime settings.
Related#
Related Articles
What is the "Is [site] down?" tool?
The is-down tool checks any public URL from an outside vantage point and tells you if the problem is you or the site itself.
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Whitelist Lemwatch monitoring IPs
Allow Lemwatch checks through your firewall, WAF, or rate limiter using our published IP ranges and User-Agent.
Cloudflare is blocking Lemwatch checks
Fix Cloudflare "Challenge", "Managed Challenge", or 1020 errors that make Lemwatch see your site as down.