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.
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.
ipconfig /flushdns (Windows) or sudo dscacheutil -flushcache (macOS)/is-down/<domain> — compare our result to your browser.
Multi-region probes are on the paid plans — see uptime settings.