502 Bad Gateway error: what to do when you can't get through to a website

Viv is trying to reach Freecycle but is getting a 502 Bad Gateway error. If you can't get through to a website, here are five things you can try....
I keep getting an error message, 502 Bad Gateway nginx/0.7.67, when I try to access the Freecycle site. I have rebooted my PC and used 'system restore' several times, but haven't been able to clear it. Do you know how to sort this out?
The 'Bad Gateway' error is coming from the server, and usually has nothing to do with your PC. It may just be that the site is overloaded. Often, simply refreshing or reloading the page (Ctrl-F5) will work, but sometimes the problem can persist for days. If so, you could log the time(s) and browser version and submit an error report to the webmaster, because 502 errors can be caused by bugs in the associated PHP programming. In this case, email the admin team at myfreecycleadmin@freecycle.org. If it's an intermittent fault, the simplest option is to wait for 10 minutes and then try again.
There are a few things that you can do to try to get through to a site when you get a 502 Bad Gateway error. It's hard to know whether they actually work. It might be that doing them is simply introducing a delay and the site would have worked if you hadn't bothered. Either way, it's useful to have a few things to try when you can't get through to any website.

Source: https://www.theguardian.com/technology/askjack/2013/aug/01/502-bad-gateway-error