The 502 Bad Gateway error is usually a network error between servers on the Internet, meaning the problem isn't typically with your computer or Internet connection.
However, it is possible that there's something wrong on your end. Work through those possibilities below.
Try loading the URL again by pressing F5 on your keyboard, or by clicking the refresh/reload button.
While the 502 Bad Gateway error is usually indicating a networking error outside of your control, it could be extremely temporary. Trying the page again will often be successful.
Start a new browser session by closing all open browser windows and then opening a new one. Then try opening the webpage again.
It's possible that the 502 error you received was due to an issue on your computer that occurred sometime during this use of your browser. A simple restart of the browser program itself could solve the problem.
Clear your browser's cache. Outdated or corrupted files that are being stored by your browser could be causing 502 Bad Gateway issues.
Removing those cached files and trying the page again will solve the problem if this is the cause.
Delete your browser's cookies. For similar reasons as mentioned above with cached files, clearing stored cookies could fix a 502 error.
Note: If you'd rather not clear all of your cookies, you could first try removing only those cookies related to the site you're getting the 502 error on. It's best to remove them all but it won't hurt to try the clearly applicable one(s) first.
Start your browser in Safe Mode. Running a browser in Safe Mode means to run it with default settings and without add-ons or extensions, including toolbars.
If the 502 error no longer appears when running your browser in Safe Mode, you know that some browser extension or setting is the cause of the problem. Return your browser settings to default and/or selectively disable browser extensions to find the root cause and permanently fix the problem.