Mac’s DNS cache isn’t something you need to worry about. It works quietly in the background, sending you to the right websites when you ask for them. But if it gets corrupted, then you can run into problems loading sites, with 404 errors being common. Clear your Mac’s DNS cache with the following command

• In the Terminal window, type the following command “sudo killall -HUP mDNSResponder”.

• Key in your computer’s admin password to proceed.