Temporary Website Outage
For three hours yesterday the website suddenly went offline. The only sign of life was a very unhelpful message: “500 Internal Server Error”. I’m happy to say that the problem has been fixed! I am writing this post in case anyone else has the same problem.
Twenty Fourteen 1.3 Update
Here at IfThen Software we use one of the default WordPress themes called Twenty Fourteen. It’s nice and simple, and gets the job done. We may upgrade in the future, but so far it’s working well: This is the first time we have had a problem with it.
I should note that I did not update WordPress to version 4.1 before updating the theme: I suspect this may have been part of the problem, but I do not have any proof.
500 Internal Server Error
The particular flavor of the glitch that I encountered was causing a “500 Internal Server Error” error whenever the website was accessed. Individual files unrelated to WordPress could be accessed, but not the main website itself.
This error is caused by a problem encountered by the web server when trying to serve a web page. It is displayed when a more specific error message cannot be provided. Usually Apache httpd will report a more detailed message in the error log. If the problem is a PHP error, there is a special error log for it as well.
Troubleshooting the Error
I tried accessing the website in both Google Chrome and Internet Explorer, just to make sure the problem wasn’t browser related. In hindsight, I should have also tried Firefox, which I will do next time. I also tried accessing the website without cookies, to make sure that it wasn’t a problem with the account system. These simple checks turned up negative, but at least I had a better idea of where the problem might be.
Just to be sure, I also rebooted the web server. This has caught errors in the past, so it was worth trying. Unfortunately, this also turned out negative.
Upon inspection, both the Apache httpd and PHP error logs were empty.
Karyl suggested disabling all plugins, which I did by following the phpMyAdmin section in this article: Two Ways to Manually Disable WordPress Plugins. But like all previous attempts, this did not resolve the 500 internal server error.
Finally, the Solution
Fortunately for my sanity, I suddenly realized that I had a backup of the Twenty Fourteen v1.2 theme. I did not know it at the time, but you can also download version 1.2 from the WordPress website.
Restoring the backup fixed the error, although temporarily. After updating the WordPress core to v4.1, the 1.3 theme update worked perfectly. I hope this article helps someone else with the same problem!