When a computer needs to do a DNS lookup it will first look in its internal cache. If the computer is not refreshing its DNS cache in a timely manner, you may need to manually clear the DNS information.

In order to run a command to flush the local DNS cache you must first open a command terminal window. There are a number of ways to flush your cache depending on your Linux distribution and the version of that distribution. Here are some of the most command commands in order of prevalence:

sudo systemd-resolve --flush-caches

sudo resolvectl flush-caches

sudo killall -USR2 systemd-resolved

sudo killall -HUP dnsmasq

sudo systemctl restart dnsmasq