Windows: Open Command Prompt as Administrator and run `ipconfig /flushdns`
Windows PowerShell: Run `Clear-DnsClientCache`
macOS: Run `sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder`
Linux with systemd-resolved: Run `sudo resolvectl flush-caches`
Linux with nscd: Run `sudo service nscd restart`
Linux with dnsmasq: Run `sudo systemctl restart dnsmasq`
Chrome: Open `chrome://net-internals/#dns` and click `Clear host cache`
Firefox: Open `about:networking#dns` and click `Clear DNS Cache`
Flush router DNS cache: Reboot the router or use its admin interface if available