When you enter a website in your address-like PCMag.com computer, you do not really know where to go alone. Instead, it looks like addressing on a Domain Name System (DNS) server that matches it with an IP address for the computer to visit.
It's like your friend says "meet me at Tom's Bistro" – if you do not know where Tom's Bistro is, you can look up the address in the phone book and drive there.
However, it may take a while to scan the directory before finding the correct address. To speed up the process, the computer saves some of these records for easy access later. To continue with the former metaphor, it's like writing down "Tom's Bistro ̵
Perhaps the site you visit changed servers, and no longer exists in the cached address, or you have a malicious code attempting to redirect common pages to malicious websites. (If you suspect that the problem could be a malicious code you can scan one of these tools . .) In any case, you can "flush" your DNS cache starts from scratch, so your computer reappears URLs on the DNS server.
This process, of course, is different from clearing the web cache from a browser. If cleaning your browser's cache does not resolve the issue, clearing your DNS cache may be the next step. Here's how to do Windows and MacOS with the command line. (If you are using Linux, you must look at instructions for your specific distribution.)
Flush the DNS Cache on Windows
If you are on a Windows machine, which Windows machine anytime, even going back to XP and earlier spooling of DNS only takes a single command. Click the Start menu and type "cmd." Right-click the command prompt and select "Run as administrator". Type the following command in the command prompt window:
ipconfig / flushdns
If successful, command prompt will report with "Clear DNS resolving buffer". Please try to visit the site and see if it resolved the issue. If not, the site may be down, you may have Wi-Fi issues, or you may have a more problematic network issue at the end that must be tracked. If this is someone else's computer, you can always try remote troubleshooting.
Macro Cache on a Mac
Mac users need to run a fast Terminal command to flush the DNS cache, but the command differs depending on your version by macOS. First, press Command + Space to open Spotlight and search for "Terminal." Press Enter to open it.
Most modern versions of macOS from OS X Lion through macOS Sierra-use the following command. Enter it in the terminal and press Enter:
sudo dscacheutil-flushcache; sudo killall -HUP mDNSResponder
If you are on OS X 10.10.1, 10.10.2 or 10.10.3, you must run this command instead:
sudo discoveryutil utnsflushcaches; sudo discoveryutil
You will not see a success message for the command, but you can check the problematic site and see if it solves the problem. If not, you must proceed to other troubleshooting steps.