This is what is says, but I am sure you have found this yourself.
The 502 Bad Gateway error is usually a network error between servers, meaning the problem is not with your computer or internet connection.
The error may be temporary. Try refreshing the webpage or re-enter the address in the address bar and check. Trying to reload the page often fixes the issue.
Since the 502 Bad Gateway error message is an issue with the web site's network, there could be a technical glitch from the server. You may want to wait for a while before loading the website.
All vids from all websites, or is it on youtube? I tried to watch videos, just doesn't tell anyone very much.