When URLs are just not resolving the way you want, to time to clear or flush the DNS nameserver local cache – enter the relevant command in the Terminal/command line for the operating system you are on.

How to flush the local DNS cache

macOS Catalina 10.15.0

sudo killall -HUP mDNSResponder

macOS Mojave 10.14.0

sudo killall -HUP mDNSResponder

macOS High Sierra 10.13.0

sudo killall -HUP mDNSResponder

macOS Sierra 10.12.0

sudo killall -HUP mDNSResponder

OSX 10.11.0

sudo killall -HUP mDNSResponder

OSX 10.10.4

sudo killall -HUP mDNSResponder

OSX 10.10.0 – 10.10.3

sudo discoveryutil mdnsflushcache

OSX 10.9  – 10.8 – 10.7

sudo killall -HUP mDNSResponder

OSX 10.5 – 10.6

sudo dscacheutil -flushcache

Windows

ipconfig /flushdns

Linux (depending on what you’re running)

/etc/init.d/named restart

/etc/init.d/nscd restart