Constantly getting '502 bad gateway' message on Chrome and Safari

Hello,

I keep getting the message 502 bad gateway on both Safari and Chrome. It happens on any website, often when I click a link/ open a new tab. Once the message comes up I am unable to use either browser. When I searched this it recommended refreshing the page and clearing all cache and browsing history. I regularly do all of this. The only way I can fix it is if I completely restart my macbook and reload the browser. However, it then happens again 2 or 3 days later. I can't find any more information of what I can do to stop this constantly happening. Can anyone suggest anything? Or could it be a problem with the macbook itself?

Thank you in advance