That’s where the error is being detected, in all probability.
Errors like this are logged. Check the error log on your server. If you can’t find the log, please contact your host.
Meantime, enable wp_debug and wp_debug_log and after an error, look at wp-content/debug.log to see if anything gets logged there. https://codex.wordpress.org/Debugging_in_WordPress
You can also try this: Please attempt to disable all plugins, and use one of the default (Twenty*) themes. If the problem goes away, enable them one by one to identify the source of your troubles.
We run our own VPS at the WHM level, so unless something is actually wrong with the server, this seems to be our problem. The error logs in these directories don’t seem to tell us much. Here is example of the error log for the “wp-includes/SimplePie” directory, the only error log is from june 26th, yet the 500 error seems to have started in the last few days:
[25-Jun-2018 16:10:41 UTC] PHP Fatal error: Class ‘SimplePie’ not found in /home/usanunch/public_html/wp-includes/SimplePie/Core.php on line 55
[26-Jun-2018 09:33:04 UTC] PHP Fatal error: Class ‘SimplePie’ not found in /home/usanunch/public_html/wp-includes/SimplePie/Core.php on line 55
[26-Jun-2018 11:23:16 UTC] PHP Fatal error: Class ‘SimplePie’ not found in /home/usanunch/public_html/wp-includes/SimplePie/Core.php on line 55
[26-Jun-2018 14:34:06 UTC] PHP Fatal error: Class ‘SimplePie’ not found in /home/usanunch/public_html/wp-includes/SimplePie/Core.php on line 55
If you go to line 55 in the Core.php file in this directory, the file consists of four lines of code:
class SimplePie_Core extends SimplePie
{
}
Error_log in /wp-content/ listed this:
[14-Feb-2017 07:50:49 UTC] PHP Warning: file_put_contents(/home/usanunch/public_html/wp-content/languages/mo.php): failed to open stream: No such file or directory in /home/usanunch/public_html/wp-content/index.php on line 19
[15-Feb-2017 06:41:28 UTC] PHP Warning: file_put_contents(/home/usanunch/public_html/wp-content/languages/mo.php): failed to open stream: No such file or directory in /home/usanunch/public_html/wp-content/index.php on line 19
[13-Apr-2017 01:17:46 UTC] PHP Warning: file_put_contents(/home/usanunch/public_html/wp-content/languages/mo.php): failed to open stream: No such file or directory in /home/usanunch/public_html/wp-content/index.php on line 19
[15-Aug-2017 03:12:13 UTC] PHP Warning: file_put_contents(/home/usanunch/public_html/wp-content/languages/mo.php): failed to open stream: No such file or directory in /home/usanunch/public_html/wp-content/index.php on line 19
It looks like you’re missing some core files.
If you can get to DASHBOARD->UPDATES, click the button to reinstall the current version of WordPress.
We have run the re install but it doesn’t change anything. Since this post we started checking other sites on different servers, some with fresh same day WP installs with no plugins installed, and we found that all sites display these errors when trying to browse these PHP files.
The new running idea is that these files aren’t meant to be indexed, or shown individually and that google doesn’t normally index them, but for some reason they did index ours (one suggestion was that an index file was somehow placed in the wp-includes directory and it was “scraped”)
We have been advised to modify our robot.txt file to exclude the wp-includes directory but we are afraid that we will be penalized by google for blocking the resource.
There’s nothing in wp-includes that google needs to index.
