502 & 504 Gateway errors

You are working away, just like always, when you see a 502 Gateway or 504 Gateway Timeout error message. What is this? First of all, let's begin with some basic definitions. 

Gateway 

A gateway is a hardware device that acts as a "gate" between two networks. It may be a router, firewall, server, or other device that enables traffic to flow in and out of the network. While a gateway protects the nodes within a network, it also a node itself. 

A gateway is a node (router) in a computer network, a key stopping point for data on its way to or from other networks. Thanks to gateways, we are able to communicate and send data back and forth. The Internet wouldn't be any use to us without gateways.

Okay, so quickly, what is a Node? 

A node is a point of intersection or connection within a network. When all devices are accessible through the network, these devices are all considered nodes. The big-picture definition of nodes are as the major centers through which Internet traffic is typically routed. 

Now that we have a couple of definitions under our belts, let's talk more about what 502 Bad Gateway and 504 Gateway Timeout error messages mean. 

A 502 Bad Gateway error means that one server on the Internet received an invalid response from another server. The server was acting as a gateway and received an invalid response from the upstream server. The server failed to fulfill a valid request. 

Gateway errors are often caused by issues between online servers.

However, sometimes, there is no real issue but your browser thinks there is an issue thanks to a problem with your browser, an issue with your networking equipment, or some other reason. 

Sometimes your browser continues to think and behave as though an issue remains long after the error has been resolved. This is because browsers cache messages. The same technology that allows your browser to recall your preferences online also causes your browser to continue to wave a flag alerting you needlessly. Now what? 

Best Practices to address persisting Gateway error messages after the issue has been resolved: 

You have been notified that the 502 or 504 Gateway error has been resolved. YAY! 

So, why does your browser continue to tell you there's still a problem? Again, ALL browsers cache messages and your browser wants to make sure it has your full attention. 

Try these steps to remedy the situation and get rid of that pesky message: 

1. Try loading the URL again by pressing F5 or Ctrl+R on your keyboard, or by clicking the refresh/reload button. Many 502 error messages are extremely short-lived and refreshing your page is all that's required. Think of Thanksgiving dinner when Aunt Mary continues to pile mashed potatoes on your plate even when you've said you're full. Refreshing your page is like waving your hand over your dish so Aunt Mary knows you're good. 

If you have a tendency to never fully log out of L2L and other Internet sessions, you are far more likely to see error messages persist long after any problem has been resolved. 

2. In addition to reloading the URL and refreshing your page view, if you work from bookmarked pages, you may have to manually enter the URL to remove the outdated error message. Again, this is because browsers cache messages.  

3. Start a new browser session by closing all open browser windows and then opening a new one. Then try opening the web page again. It's possible that the 502 error you received was due to an issue on your computer that occurred sometime during this session in your browser. A simple restart of the browser program itself could solve the problem. 

4. Clear your browser's cache. Error messages that are being stored by your browser could be causing 502 Bad Gateway error message issues. 

5. Clear your browsing history. 

6. Delete your browser cookies. 

7. Log out of all open sessions. You will need to actually LOG OUT, not just X out of all open windows. 

8. If none of the steps above resolve the persisting error message, shut down and restart your computer. 

*If you continue to see error messages, or the site is unreachable, contact the site itself. If that site is Leading2Lean, chances are good that we are already aware of and working to resolve any lingering issues.