safari can't find server

There are several websites I can't and have never been able to access from my MacBook. Whenever I try I get the message that safari can't find the server. I have spent a lot of time browsing similar discussions about this. I can't access these websites on either safari or firefox. My software is up to date. I have emptied my cache and reset safari. I know multiple people mentioned "proxies" on other discussion threads but I honestly am not computer literate so I have no idea what those are or how I'm supposed to review them. Any help would be great!!