What can cause a Wordpress Site to give a HTTP 500 error?
If you were to google for the definition of what an HTTP 500 error is, you would get something along the lines of "The 500 Internal Server Error is a very general HTTP status code that means something has gone wrong on the web site's server but the server could not be more specific on what the exact problem is." Which is very unhelpful.
This can be one of the most frustrating errors that can occur in WordPress. It rarely has a straightforward solution, requiring a lot of troubleshooting and investigating.
I would highly recommended that you backup your site before making any changes, as many times fixing this requires messing with the root directory.
Internal server errors are annoying because the error on the website doesn’t provide any information about the actual cause of the issue. The fact that it says ‘internal server error’ can be misleading, because, in almost all cases, your host (and/or server) isn’t to blame.
The two most common causes of this error are a corrupted .htaccess file or going over your server’s PHP memory limit. The .htaccess file in your WordPress directory can become corrupted after you install a plugin or make other changes to your WordPress site. The fix for this is to create a new .htaccess file.
The PHP memory limit issue usually occurs as the result of a poorly-coded plugin running on your site or a site that’s grown considerably over time and is using too many plugins. You’ll begin to exceed the PHP memory limits set by your hosting provider once either of these things happen.
If you still have access to the wordpress admin you can also try deactivating plugins to check for faulty plugins.
One good way to investigate for underlying issues on the Linode is to take a look at the error logs for the webserver. If you are running Apache, you will want to check:
On Debian and Ubuntu
If you find anything odd in there, feel free to share it as a response and we can attempt to provide additional information based on those log lines.
There are a lot of great resources for wordpress online. Wordpress has its own forum page that is full of very useful information on a broad range of issues including this one. I have posted below some links to wordpress and some other sites I think may be helpful.
We also have some additional steps that might help in this other Community Site post.
I hope this was helpful.
Are you getting a blank page, commonly referred as White Screen of Death?
This could be due to a plugin. Enable debug mode by using wp-config.php,
define('WP_DEBUG', true); define('WP_DEBUG_LOG', true); define( 'WP_DEBUG_DISPLAY', false );
Check /wp-content/debug.log for error messages.
Most likely, disabling a plugin should fix this. You need to find out which plugin is causing this.